Beyond Density Matrices: A Higher-Categorical Framework for Quantum States, Measurement, and the Arrow of Time
Full text
Beyond Density Matrices: A Higher-Categorical Framework for Quantum States, Measurement, and the Arrow of Time Andrei T. Patrascu1 1FAST Foundation, Destin FL, 32541, USA email: andrei.patr[email protected] We present a higher-categorical reformulation of quantum theory in which physical processes are modeled as morphisms in a monoidal higher category, with objects representing system sectors and coherence data encoding the rules of composition. Coherence breakdown — implemented as curvature in the associators and unitors — generates intrinsic non-unitarity and irreversibility, embedding environment-like behavior directly into the composition rules rather than introducing it as an external construct. This structural non-unitarity resolves the measurement problem by making state-update and collapse natural consequences of categorical composition, realized as idempotent splittings in the Karoubi envelope. We address Roger Penrose’s long-standing concerns about density matrices, particularly their inability to distinguish between proper (classical ignorance) and improper (entanglement-induced) mixtures, and their erasure of the geometric and historical data of pure states. In our framework, a “state” is not identified solely with an operator ρon a Hilbert space, but as a morphism-withhistory in the process category, retaining the provenance of statistical structure and distinguishing classically mixed from entanglement-reduced states. Two numerically identical density matrices in the standard formalism correspond to distinct categorical objects, preserving physical distinctions that density matrices obscure. The formalism admits a precise definition of environment-induced decoherence as the monoidal composition of dilated morphisms with discard maps, where curvature in the coherence constraints encodes irreversible leakage of information. This yields a built-in arrow of time, characterized by monotonic decay of categorical relative entropy with respect to a stationary reference object. We develop the full mathematical specification of states in this setting, analyze their evolution under curvature-induced GKSL generators and nonlinear state-dependent dynamics, and illustrate the theory with explicit diagrammatic examples. Applications include resolving ambiguities in quantum measurement theory, diagnosing irreversibility in quantum chaos, and engineering radiative channels in nuclear and condensed matter systems. Our results suggest that the higher-categorical perspective not only restores the physical clarity Penrose sought, but also unifies the description of state evolution, measurement, and temporal orientation within a single structural principle. INTRODUCTION The foundations of quantum theory have, since its inception, raised profound questions about the nature of physical states, measurement, and the emergence of classicality from quantum mechanics. The measurement problem — the tension between the unitary, deterministic evolution of quantum states according to the Schr¨odinger equation and the apparent non-unitary, stochastic collapse of the wavefunction during measurement — remains a central conceptual and technical challenge [1–3]. Standard quantum mechanics accommodates both continuous evolution and discontinuous measurement by supplementing unitary dynamics with the projection postulate, but this dual description has long been criticized for its lack of a unified dynamical framework. The density matrix formalism, introduced by von Neumann [4] and further developed by Landau [5] and others, extended quantum mechanics to describe both pure and mixed states within a single mathematical object ρ, enabling the study of statistical ensembles and open-system dynamics. This formalism has proved indispensable in quantum statistical mechanics, quantum optics, and quantum information theory [6]. Nevertheless, the density matrix formalism is not without conceptual difficulties. In particular, the same ρcan arise either from a proper mixture — a classical probabilistic mixture of pure states reflecting ignorance about the actual state — or from an improper mixture obtained by tracing out part of an entangled system [7]. While these two situations are physically distinct, the density matrix formalism treats them identically, obscuring important ontological and operational differences. Roger Penrose, in The Road to Reality [8], has emphasized this point as a deep conceptual flaw. In his view, the inability of ρto record its provenance undermines its status as a complete descriptor of a quantum state. Furthermore, Penrose has expressed dissatisfaction with the flattening of the rich projective geometry of pure states into the convex geometry of density matrices, arguing that essential physical structure is lost in this transition. He has also argued that the density matrix formalism fails to provide an adequate description of objective collapse processes, which he believes may be rooted in gravitational effects [9, 10].
2 In parallel, the study of open quantum systems has revealed that non-unitary and irreversible dynamics can emerge naturally when a system is coupled to an environment, leading to completely positive, trace-preserving (CPTP) semigroups described by the Gorini–Kossakowski–Sudarshan–Lindblad (GKSL) equation [11, 12]. These dynamics embody an arrow of time via monotonic entropy production [13], yet in standard formulations the environment is modeled as an external, auxiliary system, and irreversibility is not intrinsic to the formalism. Higher quantum mechanics from coherence breakdown In this work, we introduce a reformulation of quantum theory — higher quantum mechanics — derived from the breakdown of higher-categorical coherence conditions in a monoidal higher category of physical processes. In this setting: 1. Objects represent system sectors (Hilbert spaces, algebras, or more general state spaces), and 1-morphisms represent dynamical processes. 2. Coherence data (associators, unitors) encode how processes compose. When these coherence conditions are flat, the resulting dynamics are unitary and reversible. When they acquire curvature (coherence breakdown), composition induces intrinsic non-unitarity,nonlinearity, and irreversibility. 3. The environment is not an external add-on: it is built into the composition rules themselves through dilation and discard morphisms, so that every process has an intrinsic environment sector whose back-action is governed by the same curvature that breaks coherence. 4. The induced system dynamics are completely positive (CP) semigroups when Markovian, with GKSL generators derived from the coherence-defect tensor, rather than postulated. Outside the Markovian regime, the same structure yields CP, non-Markovian memory kernels. In this framework, a state is not merely a density operator ρ; it is a morphism-with-history — a process from the monoidal unit object to the system object, together with the coherence data that encodes its compositional provenance. This additional structure preserves the distinction between proper and improper mixtures, retains the projective geometry of pure states within the mixed-state setting, and makes the measurement problem a structural feature: measurement appears as an idempotent splitting in the Karoubi envelope, forced by the coherence breakdown itself. The curvature-induced dissipative terms in the dynamical generators naturally produce an arrow of time, characterized by a monotonic decay of categorical relative entropy with respect to a stationary reference state. This unifies the resolution of the measurement problem, the emergence of temporal orientation, and the role of the environment in open-system dynamics under a single structural principle. The present work builds on categorical quantum mechanics [14, 15], open-system theory [16], and quantum thermodynamics [17], but departs from these by embedding the environment and irreversibility into the foundational composition law itself, rather than treating them as emergent or externally added phenomena. We further connect this formulation to applications in quantum chaos in chemistry, control of nuclear radiative channels, and relativistic quantum field theory, showing that the same categorical mechanism governs irreversibility across these diverse physical regimes. PENROSE’S CRITIQUE OF DENSITY MATRICES AND A HIGHER–CATEGORICAL RESOLUTION This section formalizes (i) the ambiguity Penrose highlighted regarding density matrices, (ii) a higher–categorical notion of state with provenance that separates proper from improper mixtures, (iii) measurement as an idempotent splitting (Karoubi envelope), and (iv) the structural embedding of environment-like behavior into composition. We also give concrete diagrammatic examples and derive operational consequences. Two kinds of mixtures in the operator formalism Let Hbe a finite-dimensional Hilbert space. A density operator ρ∈ B(H) can appear in two physically distinct ways:
3 1. Proper (classical) mixture: There exist pure states {|ψki} and probabilities {pk}with Pkpk= 1 such that ρ=X k pk|ψkihψk|.(1) Operationally, a classical random variable Kselects kwith probability pkand prepares |ψki. 2. Improper (entanglement-induced) mixture: There exists an auxiliary space Kand a pure state |Ψi ∈ H⊗K such that ρ= TrK|ΨihΨ|.(2) Here the mixedness arises from discarding (tracing out) the auxiliary system. Equations (1) and (2) can yield the same operator ρ, although the underlying physics differs. This is Penrose’s concern: the operator alone does not retain provenance. Moreover, the projective geometry of the pure-state manifold is hidden once one passes to the convex set of density operators. Process categories and states with provenance We work within a (symmetric) monoidal higher category Proc of processes: •Objects: physical systems A, B, . . . (e.g., Hilbert spaces, C∗-algebras). •1-morphisms: physical processes f:A→B(unitaries, channels, measurements). •2-morphisms: refinements/coarse-grainings, homotopies of pasting diagrams; these carry coherence data. •Monoidal product:⊗with unit object I(“no system”). We assume each object Acarries a discard (counit) εA:A→I, and that certain “classical” objects Care equipped with a special commutative dagger Frobenius algebra (∆, µ, η, ε) that allows copying/erasing of classical records. Curved coherence (coherence breakdown). Associators and unitors need not be trivial: we write αA,B,C =α(0) A,B,C ◦exp{ΩA,B,C}, λA=λ(0) A◦exp{ΩL A}, ρA=ρ(0) A◦exp{ΩR A},(3) where Ω’s are (infinitesimal) 2-morphism-valued curvature tensors. Flat coherence corresponds to Ω = 0. Definition .1 (State with provenance).Astate with provenance of system Ais a pair s=s:I→A, [Γ], where sis a 1-morphism (“preparation”) and [Γ] is an equivalence class of pasting diagrams in Proc exhibiting a dilation of svia environment objects, classical records and their compositions, modulo 2-isomorphisms that preserve: (i) the classical Frobenius structure, (ii) the discard maps, and (iii) the curvature tensors in (3). There is a forgetful 2-functor U:Proc −→ CPTP,(4) to the category of completely positive trace-preserving maps on operator algebras, sending (s, [Γ]) to the usual density operator ρ=U(s, [Γ]). Penrose’s ambiguity arises because Uforgets the class [Γ]. Two provenances for the same operator and their diagrams Case A (proper mixture). Let Cbe a classical bit with copying ∆ : C→C⊗C. Let ηC:I→Cprepare the distribution {p0, p1}in the basis {|0i,|1i}. Define conditionals pi:C→Aby pi(|ii) = |ψii. The preparation is sA:= idA⊗εC◦U◦ηC, U := X i=0,1|ψiihi|C,(5) and the discard εCimplements classical marginalization. Then U(sA,[Γcl]) = Pipi|ψiihψi|.
4 Case B (improper mixture). Let Bbe an auxiliary quantum system. Prepare |Ψi ∈ A⊗Bby t:I→A⊗Band discard B: sB:= idA⊗εB◦t. (6) Then U(sB,[Γq]) = TrB(|ΨihΨ|). String-diagram summary (provenance of the same operator). Case A (proper) I C A ⊗C A Case B (improper) I A ⊗B A ηCU:|ii7→|ψiiidA⊗εC t: 17→|ΨiidA⊗εB Although U(sA,[Γcl]) = U(sB,[Γq]) may hold, the classes [Γcl] and [Γq] are inequivalent in Proc (Definition .1). Why the two provenances are inequivalent We formalize inequivalence using two structural constraints. (i) No-broadcasting vs copyability. Classical records Cadmit copying ∆, hence broadcasting. Quantum correlations do not [18]. If an equivalence existed between [Γcl] and [Γq] preserving the classical Frobenius structure, one could copy the record in Case B, violating no-broadcasting. (ii) Curved coherence obstruction. In the presence of curvature Ω in (3), the rebracketing that tries to “pull” the quantum correlation through a classical copy map acquires a defect that cannot be removed by 2-isomorphisms constrained to preserve (∆, ε) and the discard structure. Proposition .1 (Inequivalence of provenance classes).Let ρbe a fixed density operator on Athat arises both as a proper mixture (5) and as an improper mixture (6). In Proc, the state-with-provenance objects (sA,[Γcl]) and (sB,[Γq]) are not equivalent under 2-isomorphisms preserving (a) classical Frobenius structure, (b) discard maps, and (c) the curvature tensors Ω. Sketch. Assume an equivalence exists. Transporting along it, the classical record in Case A would correspond to a broadcastable structure for the quantum correlation in Case B. This contradicts the no-broadcasting theorem [18]. In the curved case Ω 6= 0, any attempt to map the rebracketing that implements classical copying to one that transmits quantum correlations necessarily introduces a nontrivial defect channel on the joint slice, which cannot be annihilated by 2-isomorphisms preserving Ω and ε; otherwise one would obtain a flat rebracketing for a noncopyable resource. Operational remark. If an observer has access only to Aand no side information, the two preparations are operationally indistinguishable, as standard quantum theory asserts. Our resolution is structural: the category retains distinct objects (s, [Γ]) that the forgetful functor Usends to the same operator. This is precisely the additional structure Penrose argued was missing. Measurement as idempotent splitting (Karoubi envelope) Let p:A→Abe an idempotent 1-morphism (p2=p) that coarse-grains outcomes; diagrammatically, p“forgets” components orthogonal to a measurement eigenspace. The Karoubi envelope Kar(Proc) adjoins splittings of all idempotents, producing objects (A, p) and morphisms commuting with p. Definition .2 (Measurement).A (projective) measurement on Ais a finite family of idempotents {pi:A→A}with pipj=δijpiand Pipi= idA. The act of measurement is the passage to the Karoubi object (A, pi)together with the discard of the orthogonal complement via the counit εA. In flat coherence (Ω = 0), idempotent splitting can be “reversible” at the level of pure process data (e.g., in dilation). With curvature, the rebracketing defects inject an intrinsic nonunitarity into the splitting, making reduction an irreversible structural step. This realizes collapse as a structural operation, not a postulate.
5 Environment as composition: Stinespring data, curvature, and GKSL Every 1-morphism f:A→Bis given together with a dilation f= (idB⊗εE)◦U◦(idA⊗ηE),(7) where Eis the environment object, ηE:I→Eprepares it, and U: (A⊗E)→(B⊗E) is a coherent core (isometry/unitary when Ω = 0). Composition is defined at the dilation level; for f2◦f1one tensors environments, rebrackets, composes cores, then discards. With curved coherence (3), the associator inserts a defect channel on the joint slice: αB,E1,E2=α(0) B,E1,E2◦exp{ΩB,E1,E2}. Coarse-graining over E1⊗E2produces a CPTP map whose generator, under a Markovian scaling limit, has the GKSL form ˙ρt=−i[H, ρt] + X a,b Kab(Ω)LaρtL† b−1 2{L† bLa, ρt},(8) with a positive semidefinite Kossakowski matrix K(Ω) 0 determined by the curvature data and the environment preparation ηE.[25] Equation (8) is derived from composition; it is not an external ansatz. Relative entropy monotones and the arrow of time Let ρ∗be a faithful stationary state for (8). The relative entropy S(ρkρ∗) = Tr ρ(log ρ−log ρ∗) (9) is a Lyapunov functional: d dtS(ρtkρ∗) = −σ(ρt)≤0, σ(ρt)≥0,(10) where σis the entropy production rate. Equality for all toccurs iff the curvature-induced dissipator vanishes on the support, i.e., the coherence is flat and dynamics reduce to unitary. Thus curvature-generated nonunitarity supplies a canonical time orientation. A resolution of Penrose’s dilemma Collecting the above, we obtain: Theorem .1 (Resolution of provenance ambiguity).There exists a conservative 2-functor U:Proc →CPTP and a refinement of the notion of state from ρ∈ B(H)to (s, [Γ]) in Proc such that: 1. If two preparations (sA,[Γcl]) and (sB,[Γq]) yield the same ρunder U, then they are inequivalent in Proc whenever (a) the classical Frobenius structure is preserved, (b) discard maps are preserved, and (c) curvature tensors are fixed (Proposition .1). 2. Measurement is realized as an idempotent splitting in Kar(Proc), with curvature ensuring intrinsic irreversibility of reduction. 3. The environment is part of the composition law (7), and curvature generically produces GKSL-type semigroups (8) with entropy production (10), thereby supplying an arrow of time. Consequently, the higher–categorical framework retains the physical distinctions that density matrices erase, resolves Penrose’s provenance objection, and unifies measurement and temporal orientation as structural features of process composition.
6 Concrete qubit example Let A=C2with computational basis {|0i,|1i}. Case A. Let Cbe a classical bit with ηC(1) = √p|0i+√1−p|1iin the classical sense (probability weights). Define U=P1 i=0 |iiA hi|C; then sA= (idA⊗εC)◦U◦ηC⇒ U(sA,[Γcl]) = p|0ih0|+ (1 −p)|1ih1|. Case B. Prepare |Φ+i=1 √2(|00i+|11i)∈A⊗Band then apply a dephasing channel Zλon Bvia coupling to its environment. Discard B: sB= (idA⊗εB)◦(idA⊗Zλ)|Φ+ihΦ+|. For λ= 1 one finds the same diagonal ρas in Case A with p=1 2. Nevertheless, [Γcl]6= [Γq] by Proposition .1; the former is broadcastable, the latter is not. Dynamical signature. Couple Ato an ancilla Rand perform a Loschmidt echo protocol. In the curved-coherence setting, the echo M(t) saturates below unity for the improper mixture provenance even when the unitary part of the dynamics is perfectly inverted, whereas for the proper mixture provenance with a protected classical record C one can, in principle, reprepare the pure branch and approach unity. The gap is a witness of the curvature-induced dissipator. Summary of Section Penrose’s critique targets the loss of provenance and geometric structure when states are represented solely by density operators. By promoting states to morphisms-with-history in a curved-coherence process category, we retain provenance, realize measurement as structural idempotent splitting, and derive environment-induced semigroups and an entropy-based arrow of time from the composition law itself. The operator ρis recovered by the forgetful functor U, but the enriched object (s, [Γ]) distinguishes proper and improper mixtures and encodes the dynamics that standard formalisms must append by hand. MATHEMATICAL SPECIFICATION OF HIGHER QUANTUM STATES AND DYNAMICS In this section we formalize the higher–categorical structure underlying the proposed framework. Our aim is to make precise how (i) coherence breakdown induces intrinsic nonunitarity, (ii) the environment is structurally embedded in process composition, and (iii) the Markovian limit yields GKSL-type generators with a built-in arrow of time. Curved coherence in a monoidal higher category Let Proc be a symmetric monoidal 2-category: •Objects: physical systems A, B, . . . •1-morphisms: physical processes f:A→B •2-morphisms: transformations between processes, encoding refinements and coherence data •Monoidal product: ⊗with unit object I In the flat case, the associator αA,B,C : (A⊗B)⊗C→A⊗(B⊗C), left unitor λA:I⊗A→A, and right unitor ρA:A⊗I→Asatisfy the Mac Lane coherence axioms strictly (up to natural isomorphism). We generalize to curved coherence: αA,B,C =α(0) A,B,C ◦eΩA,B,C ,(11) λA=λ(0) A◦eΩL A,(12) ρA=ρ(0) A◦eΩR A,(13)
7 where α(0), λ(0), ρ(0) are the flat-coherence isomorphisms and Ω’s are 2-morphism–valued curvature tensors satisfying appropriate naturality conditions. The exponential is interpreted via functional calculus in the 2-endomorphism algebra. Flat coherence corresponds to Ω = 0. Physically, Ω represents a coherence defect: a nontrivial “twist” in process rebracketing that, upon discarding parts of the system, manifests as dissipative or nonlinear terms in the effective dynamics. Dilation-based composition with embedded environment Every 1-morphism f:A→Bis given by a Stinespring-type dilation: f= (idB⊗εE)◦U◦(idA⊗ηE),(14) where: •Eis the environment object associated with f •ηE:I→Eprepares Ein a reference state •U: (A⊗E)→(B⊗E) is a coherent core (unitary/isometry when Ω = 0) •εE:E→Idiscards E Composition law. For f1:A→Bwith environment E1and f2:B→Cwith environment E2, the composite f2◦f1is defined at the dilation level: A A ⊗E1B⊗E1B⊗E1⊗E2 (B⊗E2)⊗E1C⊗E2⊗E1C idA⊗ηE1U1idB⊗ηE2 αB,E1,E2U2⊗idE1idC⊗εE2⊗εE1 Curvature ΩB,E1,E2in the associator αB,E1,E2injects an irreversible channel on (B, E1, E2) before U2is applied. Effective dynamics from curvature Let U(f) be the completely positive trace-preserving (CPTP) map obtained by interpreting fin the category of operator algebras. For a one-parameter family {Ft}of such processes generated by repeated composition of a short-time step f∆t, the curvature contribution produces: Φ∆t= id + ∆tL+o(∆t),L=−i[H, ·] + DΩ,(15) where DΩis the dissipator induced by Ω. GKSL form in the Markovian limit. If the environment resets after each step (Markovian regime), DΩtakes the GKSL form: DΩ(ρ) = X a,b Kab(Ω) LaρL† b−1 2{L† bLa, ρ}, K(Ω) 0.(16) Here Laare system operators determined by the E-coupling, and K(Ω) is a positive semidefinite Kossakowski matrix derived from the curvature tensor and the environment’s initial state. Beyond Markovianity. Without environment reset, composition yields CP, trace-preserving dynamics with memory kernel: d dtρ(t) = Zt 0 K(t−s)[ρ(s)] ds, (17) where K(τ) encodes the propagation of curvature effects along the environment’s retained degrees of freedom.
8 Nonlinear extension from state-dependent coherence If Ω depends on the current state ρ(e.g., through classical control or feedback stored in E), then DΩbecomes state-dependent: ˙ρ=−i[H(ρ), ρ] + X a,b Kab(ρ)La(ρ)ρLb(ρ)†−1 2{Lb(ρ)†La(ρ), ρ},(18) yielding a nonlinear quantum master equation. This preserves complete positivity if K(ρ)0 for all ρ. Entropy production and the arrow of time Let ρ∗be a faithful stationary state of the dynamics. Define the categorical relative entropy: S(ρkρ∗) = Tr[ρ(log ρ−log ρ∗)]. A categorical Spohn inequality holds: d dtS(ρtkρ∗) = −σΩ(ρt)≤0,(19) with σΩ≥0 the entropy production rate. Equality for all timplies DΩ= 0 and thus Ω = 0, i.e., flat coherence. This monotonic decay defines a canonical arrow of time. Physical and intuitive picture The coherence curvature Ω functions as a structural environment woven into the composition law: •In flat coherence, α, λ, ρ are “pure gauge” and processes compose unitarily; the environment, though present in dilation, can be perfectly decoupled. •With curvature, rebracketing induces leakage of information/amplitude into Ethat cannot be undone by reversing the coherent cores Ualone; this is the source of irreversibility. •Measurement arises as an idempotent splitting whose irreversibility is guaranteed by Ω. •The arrow of time is a consequence of entropy production driven by Ω, independent of any coarse-grained thermodynamic limit. This yields a unified structural origin for (i) environment-induced decoherence, (ii) measurement collapse, (iii) nonMarkovian memory effects, and (iv) the thermodynamic arrow of time, all as manifestations of a single geometric principle: the breakdown of higher-categorical coherence. APPLICATIONS AND EXAMPLES The framework described in Sections 2-4 is general, but its operational power is best appreciated through explicit examples. We work out small-scale calculations, then interpret them in physical scenarios where irreversibility, measurement, and the arrow of time are key. Example 1: Qubit system with a single curvature mode Let A=C2with computational basis {|0i,|1i} and Pauli matrices {σx, σy, σz}. Curved coherence model. We take an environment E=C2and choose the associator curvature: ΩA,E1,E2=γ(σz⊗σx⊗σx), γ ∈R,(20) acting on A⊗E1⊗E2. Physically, this corresponds to a controlled σzrotation on the system triggered by correlated σx-flips in the environments.
9 One-step channel. Let U= exp(−iθ σx⊗σx) act on A⊗E. The short-time dilation step is: f∆t= (idA⊗εE)◦eΩ ∆t◦U◦(idA⊗ηE), with ηEpreparing |0iin E,εEthe trace. Expanding to O(∆t) and tracing over Eyields: Φ∆t(ρ) = ρ−iθ ∆t[σx, ρ] + γ2∆t(σzρσz−ρ) + o(∆t).(21) Generator. The generator Lin the Markovian limit is: L(ρ) = −iθ [σx, ρ] + γ2(σzρσz−ρ).(22) This is the GKSL form with a single Lindblad operator L=σzand Kossakowski coefficient K=γ2. Entropy production. The stationary state is ρ∗=1 2I. The relative entropy S(ρtkρ∗) satisfies: d dtS(ρtkρ∗) = −2γ2Tr [(ρt−ρ∗) log ρt−(ρt−ρ∗) log ρ∗]≤0, with equality iff ρt=ρ∗. Intuitive picture. The curvature (20) injects σz-type dephasing at rate γ2, independent of the Hamiltonian rotation θσx. Even if Uis perfectly inverted, the dephasing persists, marking an irreversible arrow of time. Example 2: Measurement as structural idempotent splitting Take a qubit Aand define the projectors p0=|0ih0|,p1=|1ih1|. The measurement channel M(ρ) = p0ρp0+p1ρp1 is realized in Proc as the idempotent p=p0+p1= idAtogether with a curvature-dressed rebracketing that couples A to a classical register C. In flat coherence, pcan be split and reversed via a unitary dilation. With curvature Ω 6= 0, the rebracketing induces a dissipator on (A, C) before discard, making Mintrinsically irreversible. Example 3: Quantum chaos in chemistry In chaotic molecular dynamics, Loschmidt echoes M(t) decay rapidly but can revive if all dynamics are unitary and reversible. In our framework: •The system Ais the electronic subspace, Erepresents vibrational/rotational modes. •Curvature ΩA,E1,E2captures the breakdown of coherence when different vibrational branches recombine. •Even if the electronic Hamiltonian is time-reversed, the curvature-induced DΩprevents full revival: M(t) saturates at M∞<1. This residual decay is a signature of structural irreversibility, not mere experimental imperfection. Example 4: Nuclear radiative channel control Let Abe a nuclear two-level system (excited/ground) in a crystal lattice, Ethe photonic field modes. The curvature tensor ΩA,E1,E2is engineered via a photonic crystal to suppress coupling to phonon modes and enhance specific radiative channels: ΩA,E1,E2∼κγ(σ−⊗a† k1⊗a† k2) + h.c.,(23) with κγtunable by the local density of states (LDOS). By embedding this into the composition law, decay becomes dominantly radiative, minimizing lattice heating while retaining an intrinsic arrow of time.
16 •Each two-nucleon interaction V(2) ij corresponds to a 1-morphism f(2) ij :A→Awhose dilation couples nucleons i and jto an auxiliary environment Eij. •Composition of two such morphisms f(2) ij and f(2) jk , in the presence of nontrivial curvature Ω(ij),(jk),E in the associator, produces new effective terms coupling (i, j, k)simultaneously. Explicitly, if Uij implements V(2) ij in a dilation and Ujk implements V(2) jk , then the composite: (f(2) jk ◦f(2) ij )curved = (id ⊗εEjk ⊗εEij )◦(Ujk ⊗id) ◦eΩ(ij),(jk),E ◦(Uij ⊗id)◦(id ⊗ηEij ⊗ηEjk ) generates, after tracing out the environments, an effective operator on (i, j, k) that cannot be decomposed into a sum of pairwise terms. This is a categorically generated V(3) ijk term. Higher-body forces V(n)arise analogously from nested compositions and curvature acting on multi-environment tensor products. Provenance-aware correlations In many-body nuclear physics, one studies reduced density matrices ρ(n)and their cumulants to describe n-body correlations. In our framework, each ρ(n)is replaced by a state-with-provenance (s(n),[Γ(n)]): •s(n):I→Anis the n-body reduced preparation morphism. •[Γ(n)] records whether the correlation was: 1. Present in the initial preparation (intrinsic correlation). 2. Generated dynamically through lower-body processes with curved coherence. This distinction is lost in conventional reduced density matrices but is physically relevant: correlations generated by curved coherence typically come with irreversibility and contribute to categorical entropy production. Structural irreversibility in nuclear reactions Processes such as giant resonance damping, compound nucleus formation, and multifragmentation are often described phenomenologically with imaginary optical potentials or statistical decay models. In our setting: •The environment in the dilation includes both nucleonic and mesonic/field degrees of freedom. •Curvature in the coherence data produces a GKSL dissipator DΩwhose Lindblad operators correspond to particle emission channels, collective mode damping, or energy spreading among nucleons. •This yields irreversible evolution from the outset, rather than by adding an ad hoc imaginary term. Example: Three-nucleon force from curvature Consider nucleons labeled 1,2,3 with Hilbert spaces Hi. Let U12 and U23 be unitaries generating two-body interactions in dilations with environments E12 and E23. Introduce curvature: Ω(12),(23),E =κ(O12 ⊗O23 ⊗FE), where Oij are two-body operators on (i, j) and FEacts on the shared environmental degrees of freedom. Expanding eΩto first order in κproduces an effective operator: V(3) 123,eff ≈κTrE[(O12 ⊗O23 ⊗FE)(ρ123E)] , which is a genuine three-body force on (1,2,3).
17 Impact on ab initio nuclear structure calculations In methods such as the no-core shell model (NCSM) or coupled-cluster (CC) theory: •Curvature-generated higher-body terms can be included systematically by computing Ω-induced effective interactions at the desired order. •Provenance tracking can inform truncation schemes: dynamically generated correlations with high Imay be prioritized in active spaces. •Irreversible components DΩcould model open-system effects in reactions directly in the ab initio formalism. Astrophysical relevance In neutron star matter and supernova environments: •Threeand four-body forces are crucial for the equation of state. •Categorical curvature may model density-dependent emergence of higher-body forces via coherent composition of two-body interactions. •Irreversible channels DΩcould represent neutrino emission or bulk viscosity within the same structural framework. Summary. By embedding higher-body forces and nucleon correlations into the categorical curvature mechanism, our framework: 1. Derives n-body forces as emergent from lower-body processes plus curvature, rather than inserting them ad hoc. 2. Retains preparation history for correlations, allowing a principled distinction between intrinsic and dynamically generated correlations. 3. Provides a unified description of bound-state and reaction dynamics, with irreversibility arising structurally. This opens the possibility for a new generation of nuclear structure and reaction models in which the complexity of many-body nuclear forces is an automatic consequence of the underlying categorical geometry. Toy model: curvature-induced three-body force in a harmonic trap To illustrate the mechanism concretely, consider three spin-1 2nucleons labeled 1,2,3 in a one-dimensional harmonic trap with frequency ω. The single-particle Hamiltonian is: hi=p2 i 2m+1 2mω2x2 i. The bare two-body interaction is taken as a Gaussian: V(2) ij =V0e−(xi−xj)2/(2σ2). Dilation representation. We represent each V(2) ij as a dilation f(2) ij : f(2) ij = (id ⊗εEij )◦Uij ◦(id ⊗ηEij ), where Uij = exp(−i g Oij ⊗FEij ), with Oij acting on (i, j) and FEij on the environment Eij. Curvature insertion. When composing f(2) 12 and f(2) 23 , the associator is curved: α(12),(23),E =α(0) (12),(23),E ◦eΩ(12),(23),E . Choose: Ω(12),(23),E =κ(O12 ⊗O23 ⊗FE), with Oij proportional to V(2) ij and FEa Hermitian environment operator.
18 Effective three-body term. Expanding to first order in κand tracing over E: V(3) 123,eff ≈κhFEiEO12O23. In this harmonic-trap toy model, Oij is Gaussian in (xi−xj), so O12O23 produces a correlated three-body term peaking when x1≈x2≈x3. Physical interpretation. Even if V(3) is absent in the microscopic Hamiltonian, categorical curvature generates it from two-body inputs. In realistic nuclear structure calculations, such an induced V(3) could shift binding energies, saturation density, and spectra without adding parameters by hand. Diagrammatic view: categorical generation of V(3) We depict the categorical composition generating a 3-body force from two 2-body processes: A123 ⊗E12 A123 ⊗E12 A123 A123 ⊗E12 ⊗E23 (A123 ⊗E23)⊗E12 A123 ⊗E23 ⊗E12 A123 U12 id⊗ηE23 id⊗ηE12 α(12),(23),E U23⊗id id⊗εE23 ⊗εE12 The curvature in α(12),(23),E injects a correlated interaction on nucleons (1,2,3) before U23, generating V(3) after discarding E12 and E23. Comparison with chiral EFT treatment Implications for nuclear theory Unified mechanism. In our approach, the same curvature tensor Ω: •Generates n-body forces from lower-body inputs. •Produces irreversible channels DΩfor reaction dynamics. •Encodes provenance for correlation analysis. Bridging structure and reactions. This enables a consistent treatment of: •Bound nuclei: where curvature shifts binding energies and spectra via induced higher-body terms. •Nuclear reactions: where the same curvature drives damping and dissipation without external optical potentials. Computational pathways. Ab initio codes (NCSM, CC, IMSRG) could incorporate Ω by: 1. Encoding V(2) as dilation-based morphisms. 2. Computing Ω-dressed compositions to generate V(3), V (4), . . . . 3. Including DΩterms directly in time-evolution for reaction modeling.
19 Aspect Chiral EFT Categorical curvature framework Origin of V(3) Appears at N2LO from pion-exchange diagrams and contact terms; parameters fit to data. Emerges from composition of V(2) morphisms with curved coherence; parameters κfrom categorical curvature, potentially linked to microphysics of E. Treatment of higher-body forces Added order-by-order in expansion, with increasing complexity. Automatic from the same curvature mechanism for any order; no separate derivation for V(4), etc. Correlation tracking Not explicit; reduced density matrices lose preparation history. Provenance-aware states distinguish intrinsic vs. dynamically generated correlations. Irreversibility Not inherent; requires open-system extensions. Built in via DΩfrom the same curvature generating V(n). Computational incorporation Requires recalculation of matrix elements for each new term. Effective interactions generated systematically from Ω and existing V(2) inputs. TABLE I: Chiral EFT vs. categorical curvature framework. Astrophysical link. In neutron stars and supernovae, curvature-generated n-body terms could impact the highdensity equation of state, while DΩcould describe dissipative processes such as neutrino cooling. Summary of nuclear application The categorical curvature framework thus offers a structural origin for higher-body forces and nucleon correlations, removing the need for their ad hoc introduction, and providing a unified dynamical treatment for both structure and reactions with irreversibility built in. This is particularly appealing for extending nuclear models to extreme environments where many-body and dissipative effects are both significant. Numerical estimate: induced V(3) in the harmonic trap toy model We now provide explicit numerical estimates for the energy shift produced by the curvature-induced three-body force in the toy model of Section . Model parameters. We choose natural units ~= 1 and set: m= 938 MeV/c2(nucleon mass), ω= 5 MeV, σ = 1.0 fm, V0=−50 MeV, g = 0.3, κ = 0.15, hFEiE= 1. The trap length is b=q1 mω ≈4.56 fm. Two-body Gaussian operator. The two-body operator Oij is taken as: Oij =e−(xi−xj)2/(2σ2), with matrix elements in the harmonic oscillator basis {φn(x)}given by: hninj|Oij|n0 in0 ji=Zdxidxjφ∗ ni(xi)φ∗ nj(xj)e−(xi−xj)2/(2σ2)φn0 i(xi)φn0 j(xj). Numerically, we truncate to ni, nj≤1 for a minimal estimate.
20 Curvature-induced V(3).From the expansion: V(3) 123,eff ≈κhFEiEO12O23, we compute the expectation value in the ground state Φ0(x1, x2, x3) of the noninteracting 3-nucleon trap. The Gaussian integrals can be evaluated analytically for the chosen HO length b, yielding: hΦ0|O12O23|Φ0i ≈ 1 p1+3σ2/b2·1 p1+3σ2/b2≈0.87. Thus: ∆E(3) curv ≈κ×0.87 ≈0.130 MeV. Interpretation. Even for modest curvature κ= 0.15 and weak g, the induced V(3) shifts the 3-nucleon ground-state energy by ∼130 keV. In realistic nuclear systems, such contributions can accumulate and play a significant role in fine-tuning binding energies and excitation spectra. Scaling with κand σ.Repeating the calculation for σ= 0.8,1.2 fm and κfrom 0.05 to 0.25 gives: σ(fm) κhO12O23i∆E(3) curv (MeV) 0.8 0.05 0.91 0.0455 0.8 0.15 0.91 0.1365 0.8 0.25 0.91 0.2275 1.0 0.05 0.87 0.0435 1.0 0.15 0.87 0.1305 1.0 0.25 0.87 0.2175 1.2 0.05 0.83 0.0415 1.2 0.15 0.83 0.1245 1.2 0.25 0.83 0.2075 The induced V(3) scales linearly with κand is only weakly dependent on σfor σ/b .0.3. Conclusion for the toy model. These numerical values show that even modest curvature produces measurable V(3) contributions. In realistic nuclear Hamiltonians, curvature could explain part of the empirical need for three-body force terms in chiral EFT fits, and could do so without introducing independent low-energy constants for each n-body term. Combined scaling plots for ∆E(3) curv Figure 1 presents (top) the 3D surface of the curvature-induced three-body energy shift ∆E(3) curv as a function of the Gaussian range σand curvature strength κ, and (bottom) the corresponding contour map. The surface highlights the near-linear scaling with κ, while the contours make it easy to read off values for specific (σ, κ) pairs. WHY THIS IS NOT A HIDDEN-VARIABLES THEORY (AND NOT BOHM OR ORCH OR) Our framework enlarges the notion of a quantum state from a density operator ρto a state-with-provenance (s, [Γ]) in a monoidal higher category of processes. This extra structure records the composition history of the preparation, and coherence curvature Ω in the composition rules yields intrinsic nonunitarity/irreversibility. None of this entails hidden variables, Bohmian trajectories, or gravitational objective reduction. We summarize the distinctions. Not a hidden-variables model 1. No ontic λspace, no outcome determinism. We do not posit underlying variables that assign definite pre-existing values to all observables. Measurement outcomes remain Born-rule probabilistic and contextual.
21 Bohmian mechanics This work Ontic variables Particle/worldline beables; preferred foliation often needed in QFT None. Only process histories (s, [Γ]) within standard quantum objects Dynamics Deterministic guidance equation + unitary ψ Linear dilations + curved composition ⇒CPTP semigroups (GKSL) and memory kernels Collapse Effective (epistemic) via conditional wavefunction Structural idempotent splitting; irreversibility from curvature Ω Nonlocality Ontic nonlocality in guidance No extra nonlocal resources beyond ordinary entanglement; locality respected by CPTP composition Empirical departures None (empirically equivalent to QM) Testable: Loschmidt-echo asymmetry λΩ>0, provenance-sensitive probes (I>0) TABLE II: Bohmian mechanics vs. this work. 2. Operational enrichment, not ontic supplementation. The provenance [Γ] codifies what extra degrees of freedom were actually involved (classical registers, ancillas, controllable environment modes) in building the state. If those carriers are genuinely discarded, (s, [Γ1]) and (s, [Γ2]) with the same ρbecome operationally indistinguishable—exactly as in standard QM. 3. Local CPTP dynamics ⇒no signaling. Curvature-induced dynamics on an accessible subsystem are completely positive and trace-preserving (CPTP). For any bipartite state ρAB and any local CPTP map ΦAon A, ρ0 B= TrA (ΦA⊗idB)(ρAB)=ρB, so choices at Acannot signal to B. Nonlinearities appear only as effective state-dependence after dilations and discards; on the enlarged space they are linear CPTP, avoiding the usual Gisin-type superluminal pitfalls. How it differs from Bohmian mechanics Bohmian (pilot-wave) theory introduces additional beables (particle positions) guided by the wavefunction, yielding deterministic trajectories and effective collapse via conditionalization. In contrast: How it differs from Penrose’s Orch OR / objective reduction Penrose’s objective reduction (and Orch OR with Hameroff) posits gravity-related collapse: when the gravitational self-energy EGof a superposition exceeds a threshold, reduction occurs on a timescale τ∼~/EG; in Orch OR, biological microtubules are proposed as orchestrating sites. Our approach is orthogonal: 1. No gravity-triggered collapse postulate. We do not invoke EGthresholds, special spacetimes, or microtubule mechanisms. Collapse-like reduction is the idempotent splitting in the Karoubi envelope, made irreversible by coherence curvature Ω. 2. Environment-in-composition vs. new physics. Irreversibility and decoherence arise because composition itself is curved; the “environment” is intrinsic to the process calculus, not an add-on, and no non-quantum collapse law is introduced. 3. Timescales from structure, not gravity. The decay rates (e.g., echo rate λΩ) come from categorical curvature and coupling to controllable ancillas/modes, not from gravitational self-energy estimates. This yields lab-testable predictions across platforms (qubits, ions, molecular systems), independent of biology.
22 Minimal consistency checklist •Born rule, contextuality, Bell/KS bounds: preserved. •No-signaling: guaranteed by locality of CPTP composition; effective nonlinearities arise only after discards on enlarged spaces. •QM limit: when curvature Ω = 0 or provenance carriers are discarded, the theory reduces to standard unitary QM/Open-QM with density matrices. •New empirical content: curvature-induced irreversibility (echo asymmetry), and provenance-divergence Iwhen history carriers are accessible. Takeaway. We do not restore classical realism or add hidden beables. We upgrade the notion of state to carry its compositional history and make irreversibility a structural property of process composition. This preserves the quantum core while delivering concrete, testable departures from the “all-histories-erased” density-matrix idealization—without resorting to Bohmian beables or Orch OR’s gravity-driven collapse. DISCUSSION AND OUTLOOK The central conceptual motivation for this work stems from Penrose’s long-standing critique of the density matrix formalism: that it erases essential physical information about the provenance of a state, conflating classically mixed and entanglement-induced (improper) mixtures, and thereby obscuring both their physical interpretation and potential operational distinctions [8]. In standard quantum theory, two preparations that lead to the same density operator ρ are indistinguishable at the formal level, even if they differ in physical origin, reversibility properties, or dynamical stability under subsequent evolution. Higher–categorical resolution of Penrose’s dilemma By representing quantum states as states-with-provenance (s, [Γ]) in a monoidal 2-category of processes Proc, we have formally separated the operator ρobtained from the state via the forgetful functor Ufrom the equivalence class [Γ] of its compositional history. This extra categorical layer: 1. Retains the distinction between proper and improper mixtures. 2. Records whether correlations were present ab initio or generated dynamically. 3. Allows these distinctions to enter quantitatively into the definition of the categorical entropy Scat. From the categorical perspective, Penrose’s criticism is resolved by embedding the Hilbert-space state in a richer morphism structure, in which the degeneracy between distinct physical situations is lifted. Curvature as a structural source of nonunitarity A key technical result is that curvature Ω in the coherence data of Proc acts as a universal generator of: •Nonunitary dynamics in the form of a completely positive, trace-preserving (CPTP) semigroup Φtwhose generator has GKSL form in the Markovian limit [Eq. (16)]. •Non-Markovian memory kernels when environment sectors are not reset between compositions. •Nonlinear evolution laws when Ω depends on the evolving state. This construction does not require introducing an external, model-dependent environment. Instead, the environment is intrinsic to the process composition law, and the same structural mechanism that generates the environment also generates irreversible dynamics.
23 Categorical entropy and the arrow of time We have defined the categorical relative entropy Scat(sks∗) = S(ρkρ∗) + I([Γ]k[Γ∗]), as the sum of the standard Umegaki relative entropy of the operator part and a provenance divergence Iquantifying structural differences in preparation history. Theorem .1 and the categorical Spohn inequality [Eq. (27)] show that Scat is nonincreasing under Proc-morphisms with curvature, and strictly decreasing unless Ω = 0. This identifies the arrow of time with the monotonic decay of a quantity that is sensitive to both the statistical and structural aspects of a state. Comparison with existing frameworks Standard open quantum systems. The GKSL structure is usually derived by coupling the system to an explicit environment and making Born–Markov approximations. Here, the GKSL dissipator DΩemerges from curved coherence without positing a separate external bath, and applies equally to finite and infinite environments. Chiral EFT and many-body nuclear theory. In chiral EFT, higher-body forces enter order-by-order in the expansion, with separate low-energy constants. In our framework, higher-body forces are generated automatically from lower-body morphisms via curvature, potentially reducing the number of independent fitted parameters and providing a geometric origin for observed n-body effects. Modular theory in algebraic QFT. Araki relative entropy is recovered from Scat when provenance divergence I vanishes. In curved coherence, I>0 can encode differences between modular flows generated from distinct preparation histories of the same algebraic state. Resource theories. Resource monotones given by relative entropy to the free set are recovered from Scat when I= 0. When I>0, additional “hidden” resources arise from preparation history, even if ρis free in the conventional sense. Boltzmann–Gibbs statistical mechanics. For commutative objects, Scat reduces to Boltzmann entropy difference plus a provenance term measuring nonequilibrium history. This extends thermodynamic reasoning to settings where history matters independently of macroscopic state variables. Experimental tests of curvature-induced irreversibility Section outlined protocols for detecting: 1. Curvature Ω:via Loschmidt echo asymmetry, where λΩ>0 signals irreversible channels. 2. Provenance divergence I:via preparation-dependent probe measurements on states with identical ρbut different histories. 3. Entropy production: by splitting σcat into σvN and σIcomponents through tomography and provenance-sensitive probing. Platforms such as superconducting qubits, trapped ions, ultracold molecules, and photonic nuclear environments could implement these tests with present or near-future technology. Implications and future directions Our results suggest several lines of future investigation: •Foundations: Explore whether curved coherence can emerge from a deeper theory (e.g., quantum gravity, spacetime discreteness) and whether Ω has a universal scaling. •Nuclear structure: Incorporate curvature-generated n-body forces into ab initio nuclear codes and compare to phenomenological fits in chiral EFT.
24 •Quantum field theory: Study curvature effects on modular flow and entanglement wedges in holographic dualities. •Thermodynamics: Develop a fully categorical formulation of fluctuation theorems using Scat. •Experiments: Quantify λΩand Iin table-top setups to constrain possible curvature values. Closing remark. By embedding quantum dynamics in a higher-categorical structure with curved coherence, we have unified the origins of irreversibility, the arrow of time, measurement collapse, and higher-body interactions within a single geometric principle. This approach resolves long-standing conceptual issues with the density matrix formalism, honors Penrose’s call for a deeper description of quantum state structure, and offers concrete experimental and computational paths forward. We believe this framework has the potential to reshape both the foundations and applications of quantum theory, from nuclear physics to cosmology. STATEMENTS •Data Availability Statement: No Data associated in the manuscript •The author declares no conflict of interests [1] J. von Neumann, Mathematical Foundations of Quantum Mechanics, Princeton University Press, 1932. [2] J. A. Wheeler and W. H. Zurek (eds.), Quantum Theory and Measurement, Princeton University Press, 1983. [3] A. Bassi, K. Lochan, S. Satin, T. P. Singh, and H. Ulbricht, “Models of wave-function collapse, underlying theories, and experimental tests,” Rev. Mod. Phys., vol. 85, pp. 471–527, 2013. [4] J. von Neumann, “Thermische Gleichgewicht im quantenmechanischen System,” G¨ottinger Nachrichten, pp. 273–291, 1927. [5] L. Landau, “Das D¨ampfungsproblem in der Wellenmechanik,” Zeitschrift f¨ur Physik, vol. 45, pp. 430–441, 1927. [6] M. A. Nielsen and I. L. Chuang, Quantum Computation and Quantum Information, 10th Anniversary Edition, Cambridge University Press, 2010. [7] B. d’Espagnat, Conceptual Foundations of Quantum Mechanics, 2nd Edition, Addison-Wesley, 1976. [8] R. Penrose, The Road to Reality: A Complete Guide to the Laws of the Universe, Jonathan Cape, London, 2004. [9] R. Penrose, “On Gravity’s Role in Quantum State Reduction,” Gen. Rel. Grav., vol. 28, pp. 581–600, 1996. [10] R. Penrose, “Quantum computation, entanglement and state reduction,” Phil. Trans. R. Soc. Lond. A, vol. 356, pp. 1927– 1939, 1998. [11] G. Lindblad, “On the generators of quantum dynamical semigroups,” Commun. Math. Phys., vol. 48, pp. 119–130, 1976. [12] V. Gorini, A. Kossakowski, and E. C. G. Sudarshan, “Completely positive dynamical semigroups of N-level systems,” J. Math. Phys., vol. 17, pp. 821–825, 1976. [13] H. Spohn, “Entropy production for quantum dynamical semigroups,” J. Math. Phys., vol. 19, pp. 1227–1230, 1978. [14] S. Abramsky and B. Coecke, “A categorical semantics of quantum protocols,” in Proceedings of the 19th Annual IEEE Symposium on Logic in Computer Science (LICS 2004), pp. 415–425. [15] P. Selinger, “A survey of graphical languages for monoidal categories,” in New Structures for Physics, Springer Lecture Notes in Physics, vol. 813, pp. 289–355, 2011. [16] H. P. Breuer and F. Petruccione, The Theory of Open Quantum Systems, Oxford University Press, 2002. [17] M. Esposito and C. Van den Broeck, “Three detailed fluctuation theorems,” Phys. Rev. Lett., vol. 104, 090601, 2010. [18] H. Barnum, C.M. Caves, C.A. Fuchs, R. Jozsa, B. Schumacher, ”Noncommuting Mixed States Cannot Be Broadcast,” Phys. Rev. Lett. 76, 2818 (1996). [19] W.F. Stinespring, ”Positive Functions on C*-algebras,” Proc. Amer. Math. Soc. 6, 211 (1955). [20] K. Kraus, ”General state changes in quantum theory,” Ann. Phys. 64, 311–335 (1971). [21] M.-D. Choi, ”Completely positive linear maps on complex matrices,” Linear Algebra Appl. 10, 285–290 (1975). [22] Steven C. Pieper and R. B. Wiringa, “Quantum Monte Carlo calculations of light nuclei,” Annual Review of Nuclear and Particle Science, vol. 51, pp. 53–90, 2001. doi:10.1146/annurev.nucl.51.101701.132506 [23] Evgeny Epelbaum, Hans-Werner Hammer, and Ulf-G. Meißner, “Modern theory of nuclear forces,” Reviews of Modern Physics, vol. 81, pp. 1773–1825, 2009. doi:10.1103/RevModPhys.81.1773 [24] Hans-Werner Hammer, Sebastian K¨onig, and Ulf-G. Meißner, “Nuclear effective field theory: Status and perspectives,” Reviews of Modern Physics, vol. 92, 025004, 2020. doi:10.1103/RevModPhys.92.025004 [25] Beyond the Markovian window, the same construction yields CP, time-nonlocal memory kernels K(t, s) via composition of dilations dressed by α=α(0)eΩ.
25 FIG. 1: Curvature-induced three-body energy shift in the harmonic trap toy model. Top: 3D surface plot of ∆E(3) curv(σ, κ). Bottom: Contour projection of the same data.