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arXiv:2610.25703

Distributed Phase Tags: A Locality-Preserving Realification Compiler for Misty-State Quantum Programs

Dan-Adrian German, Tony Newton

quant-phSubmitted Oct 19, 2026• Announced Oct 20, 2026• 0 citations
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Abstract

Complex amplitudes can be simulated over real Hilbert spaces by adjoining a two-dimensional real/imaginary degree of freedom. In a multipartite program, however, one globally shared phase tag is not a locality-preserving program transformation: every party would have to act on the same auxiliary system. We recast the distributed real simulation of multipartite quantum mechanics as a syntax-directed compiler into a real misty-state intermediate language. For $n$ parties we give explicit phase-reference codewords $|0\rangle_{P_n}$ and $|1\rangle_{P_n}$ on $n$ local tags and prove that the same real operator $J=XZ$ on any single tag realizes the logical action of multiplication by $i$. If a complex party-local gate is $A=A_R+iA_I$, its real translation is \[ \widehat A_j=A_R\otimes I+A_I\otimes J_j, \] which acts only on party $j$'s data and local phase tag. We prove an intertwining theorem for arbitrary finite party-local pure-state circuits, exact preservation of computational-basis measurement probabilities, preservation of the run-time interaction graph, and one-rebit-per-party overhead. For the canonical three-party GHZ program, the translation lies entirely inside the ordinary black-and-white misty gate fragment: controlled-$J$ replaces the complex phase operation, while the invariant $J_jJ_k|0\rangle_P=-|0\rangle_P$ transfers the required branch sign. This yields a short correctness proof for all four promised GHZ inputs and explains the earlier 64-path cancellation calculation at a single logical phase-code boundary. We distinguish this program realification problem from the weaker task of finding any real strategy with the same correlations, and state precisely which parts are known real-Hilbert-space simulation and which parts belong to the misty-language compilation layer developed here.

Comments
12 pages, 4 figures, 2 appendices

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The complete code is n bits for an n-bit word; reconstruction is exact but not generic compression. P(x) = J(x) if J(x) ≠ x; P(x) = C(x) otherwise. The canonical address is an exact re-labeling of word space. T is a native address successor. A raw k-bit transport shift, a partner read, and T are separate operators. In particular, declaring an edge between successive catalog addresses does not establish that the corresponding conformations are molecular neighbors. Three interfaces must not be conflated. The native ring successor T is a step in canonical address order. The geometric word rewrite is a change of chain conformation. A measurement/readout R extracts a specified property of the state. In particular, T does not become a protein move simply because it is a reversible permutation. The twisted one-inverter clock and temporal reader The “One Inverter” paper derives the affine twisted rotation τ(x₀…xₙ₋₁)=x₁…xₙ₋₁¬x₀, so after k ticks the first k departing bits are returned complemented. At k=n it is global complement; at k=2n the state returns. The inward terminal reader is exactly the XOR of the two central word bits. Under τ, its temporal trace reads each adjacent difference around the cyclic word, with one known inverted crossing. τᵏ(x) = rotlₖ(x) ⊕ (2ᵏ − 1), 0 ≤ k ≤ n; τⁿ = C, τ²ⁿ = I. r(x) = xₙ/₂₋₁ ⊕ xₙ/₂ ; ⊕ₜ₌₀ⁿ⁻¹ r(τᵗ x) = 1. [even n] The n−1 independent adjacent differences plus one native face bit recover the word. The two-bit closed complement-feedback rule is τ², not a new primitive. None of this creates a physical molecule; it gives a provably executable, invertible substrate for how a local reader can obtain and return distinctions. Odd-lane locks and relational deviations For odd q and n=qs, the alternating-complement lift Λq(u)=u‖Cu‖u‖…‖u is invariant under the twisted clock and intertwines J, C, and P. A center trace of period s identifies this lock and supports exact reconstruction through the first s-bit lane. In the full q-lane state, de-staggered lane differences and one anchor preserve all n bits. τₙ Λq = Λq τₛ ; Pₙ Λq = Λq Pₛ ; dH(Λq u,Λq v) = q · dH(u,v). These differences were formerly called “defects.” They are lawful relational deviations from a selected lock—not failures of the transformation. Under common affine transport, differences rotate and preserve weight. An external input can alter them at a known boundary, but selecting an input law is not already derived by the native permutation. The native address T, the twisted clock τ, and the geometric pivot defined later remain separate typed operators. The exact E/G route has n bits for a general n-bit input. A locked multi-lane family instead requires only its independent local state and the stated lift rule; the reduction comes from a demonstrated invariant restriction, not from labeling an arbitrary large input “locked.” Which operations the embedding preserves The One Inverter temporal read is an operational return path, not just a yes/no label. For n=2h, define the cyclic adjacent differences Dᵢ=xᵢ⊕xᵢ₊₁ (indices modulo n) and the observed center trace yₜ=r(τᵗx). The twisted boundary contributes exactly one inverted crossing. Over n ticks the center presents n relations; their XOR equals one, and n−1 of them together with the retained canonical face bit reconstruct the entire original word. The E/G inward/outward route supplies a separate exact return by retained qualifiers. Neither return is compression of arbitrary n-bit words. yₜ = D₍ₕ₋₁₊ₜ₎ mod n ⊕ [t=h], ⊕ₜ₌₀ⁿ⁻¹ yₜ = 1; (y₀,…,yₙ₋₂, face) ↔ x. The two masks must not be conflated. The mirror shell lamps are gⱼ=xⱼ⊕xₙ₋₁₋ⱼ, the paired entries in x⊕J(x). The dist

•Oct 23, 2026•0 citations
Complex amplitudes can be simulated over real Hilbert spaces by adjoining a two-dimensional real/imaginary degree of freedom. In a multipartite program, however, one globally shared phase tag is not a locality-preserving program transformation: every party would have to act on the same auxiliary system. We recast the distributed real simulation of multipartite quantum mechanics as a syntax-directed compiler into a real misty-state intermediate language. For nnn parties we give explicit phase-reference codewords ∣0⟩Pn|0\rangle_{P_n}∣0⟩Pn​​ and ∣1⟩Pn|1\rangle_{P_n}∣1⟩Pn​​ on nnn local tags and prove that the same real operator J=XZJ=XZJ=XZ on any single tag realizes the logical action of multiplication by iii. If a complex party-local gate is A=AR+iAIA=A_R+iA_IA=AR​+iAI​, its real translation is [
\widehat A_j=A_R\otimes I+A_I\otimes J_j, ] which acts only on party jjj's data and local phase tag. We prove an intertwining theorem for arbitrary finite party-local pure-state circuits, exact preservation of computational-basis measurement probabilities, preservation of the run-time interaction graph, and one-rebit-per-party overhead. For the canonical three-party GHZ program, the translation lies entirely inside the ordinary black-and-white misty gate fragment: controlled-JJJ replaces the complex phase operation, while the invariant JjJk∣0⟩P=−∣0⟩PJ_jJ_k|0\rangle_P=-|0\rangle_PJj​Jk​∣0⟩P​=−∣0⟩P​ transfers the required branch sign. This yields a short correctness proof for all four promised GHZ inputs and explains the earlier 64-path cancellation calculation at a single logical phase-code boundary. We distinguish this program realification problem from the weaker task of finding any real strategy with the same correlations, and state precisely which parts are known real-Hilbert-space simulation and which parts belong to the misty-language compilation layer developed here.
This work introduces a complete and self-consistent framework for quantum computation within the domain of real-valued quantum mechanics. Standard quantum computation is predicated on the manipulation of states in a complex Hilbert space, where a complex phase is a critical resource. We demonstrate that this complex structure is not fundamental but can be fully reproduced by a real-operator algebra. Our formalism is built upon a rigorous algebraic isomorphism between the imaginary unit i and the temporal Hilbert transform operator Ht\mathcal{H}_tHt​, which acts as a physical generator of phase. Leveraging this isomorphism, we systematically redefine the fundamental quantum logic gates-including the Pauli, Hadamard, phase rotation, and CNOT gates-entirely within a real operator algebra. We prove that each gate's action on a real-valued qubit state representation is mathematically and operationally equivalent to its conventional complex counterpart. The Pauli-Y, phase, and controlled-phase gates, which are intrinsically complex in the standard model, are shown to correspond to real-operator matrices involving the Hilbert transform. This formulation provides a physically grounded interpretation of quantum logic, where abstract phase manipulation corresponds to the application of a concrete, albeit non-local, integral transform. We demonstrate how this framework correctly reproduces the generation of quantum entanglement and establishes a consistent measurement theory via an Analytic Born Rule in Unified Quantum Mechanics. This work solidifies the viability of a complete real-valued model for quantum information processing and suggests new paradigms for the physical implementation of quantum hardware.
Many mainstream quantum programming languages confine higher-order structure to a classical host while restricting the quantum layer to first-order operations on qubits. This paper presents Granthi, a purely unitary higher-order quantum programming language built on three design commitments: quantum programs are first-class values that may be passed, returned, and coherently composed; additive structure is tag-preserving routing rather than observational branching, so control may remain in superposition; and programmer-facing finite label types with staged reversible-operation bindings provide domain-level control spaces without exposing tag management. These bindings are eliminated by elaboration before Source typing. Granthi deterministically normalizes each Source program to a canonical wiring form. Every well-typed Source program, including a term of function type, has a unitary boundary interpretation. Under backend correctness (BC), the reference compiler produces a unitary circuit realizing that interpretation. Granthi's currently supported executable fragment is implemented end-to-end: an OCaml DSL elaborates surface programs through a higher-order Core IR to executable quantum circuits via pytket. The language directly supports the pure-unitary quantum switch for explicitly supplied operations; closed instances compile to static circuits. It also supports interference on control-flow history and structured finite control, all within the purely unitary fragment
The properties of deterministic LOCC transformations of three qubit pure states are studied. We show that the set of states in the GHZ class breaks into an infinite number of disjoint classes under this type of transformation. These classes are characterized by the value of a quantity that is invariant under these transformations, and is defined in terms of the coefficients of a particular canonical form in which only states in the GHZ class can be expressed. This invariant also imposes a strong constraint on any POVM that is part of a deterministic protocol. We also consider a transformation generated by a local 2-outcome POVM and study under what conditions it is deterministic, i.e., both outcomes belong to the same orbit. We prove that for real states it is always possible to find such a POVM and we discuss analytical and numerical evidence that suggests that this result also holds for complex states. We study the transformation generated in the space of orbits when one or more parties apply several deterministic POVMs in succession and use these results to give a complete characterization of the real states that can be obtained from the GHZ state with probability 1.
We generalize the polynomial-time outcome-complete simulation algorithm for stabilizer circuits in arXiv:2309.08676 to track global phases exactly, yielding what we call phased outcome-complete simulation. The original algorithm enabled equivalence checking of stabilizer circuits with intermediate measurements and conditional Pauli corrections for all input states and all measurement outcomes simultaneously, but it tracked quantum states only up to a global phase. Our generalization removes this limitation and enables equivalence checking for an important family of non-stabilizer circuits: stabilizer circuits augmented with single-qubit rotations exp⁡(iαZ)\exp(iαZ)exp(iαZ) by symbolic angles. Two such circuits are equivalent if they implement the same quantum channel for all values of the symbolic angles and all measurement outcomes, given a one-to-one correspondence between rotation angles in the two circuits and a mapping between measurement outcomes. This model enables testing of compilation algorithms that transform the Clifford portions of a computation while preserving rotation angles. Examples include Pauli-based computation, edge-disjoint path compilation for surface codes, and custom compilation strategies for reversible circuits such as adders, multipliers, and table lookups. Our efficient classical verification methods extend naturally to circuits with outcome-parity-conditional Pauli gates and intermediate measurements, features that are ubiquitous in fault-tolerant quantum computing but are rarely addressed by existing equivalence-checking approaches.
We study when block-coupled regular graphs can realize prescribed complex quantum-like (QL) bit states as exact synchronized eigenstates. Two regular subgraphs GAG_AGA​ and GBG_BGB​ supply normalized all-ones eigenvectors VAV_AVA​ and VBV_BVB​, and algebraically regular bipartite couplings reduce the full graph-supported operator exactly to a 2×22\times 22×2 effective block on S=span⁡{∣0⟩,∣1⟩}\mathcal S=\operatorname{span} \{ \lvert 0\rangle, \lvert 1\rangle \}S=span{∣0⟩,∣1⟩}. Within this reduction we prove that two natural symmetric complexifications are not universal for state synthesis under a real-spectrum requirement: complex symmetric coupling with real diagonal regularities forces the target computational basis amplitude ratio r=ω2/ω1r=ω_2/ω_1r=ω2​/ω1​, for ∣ψ⟩=ω1∣0⟩+ω2∣1⟩\lvert ψ\rangle = ω_1\lvert 0\rangle + ω_2\lvert 1\rangle∣ψ⟩=ω1​∣0⟩+ω2​∣1⟩, to satisfy r2∈Rr^2\in\Rr2∈R, while real symmetric coupling with complex diagonal regularities forces r+1/r∈Rr+1/r\in\Rr+1/r∈R. Replacing complex symmetry by Hermitian coupling removes this phase obstruction. For any nonbasis target state, any prescribed real eigenvalue, and any prescribed nonzero signed spectral gap, a Hermitian weighted coupling realizes the target exactly. Additionally, an independently tuned directed-coupling model gives a second universality mechanism. We then pass from continuous effective parameters to finite weighted graphs with entries in {0,±1,±i}\{0, \pm1, \pm i\}{0,±1,±i} (the fourth roots of unity and zero), characterize the balanced discrete coupling lattice by perfect matchings, and show that exact discrete Hermitian realizations are dense in the synchronized pure-state space. These results give a state-synthesis universality taxonomy for complex QL-bits and identify Hermitian conjugate pairing as the robust structural mechanism that supports arbitrary complex amplitudes with real two-level spectra.
The NEXUS Quantum Compiler Mathematical-Space Execution and Constrained Molecular Folding Native reversible routes · quantum-sector reduction · legal molecular transformations · classical execution Driven by Dean A. Kulik · October 2026 ABSTRACT A quantum-compatible mathematical state space can be compiled and executed on ordinary classical hardware when its constraints, return paths, and observable symmetry sectors are explicitly represented. This manuscript integrates two complementary NEXUS studies without replacing either with a shorter summary. The first examines the exact native ring and E/G return machinery and audits an earlier quantum lattice-protein simulation whose eight-address mixer introduced four transitions through invalid padding states. It derives the short-time leakage coefficient 49/75, explains the distinction between finite penalties and exact subspace preservation, identifies the disconnected projected graph, and records the approximation and environmental-return requirements. The second advances to a self-avoiding honeycomb-chain compiler in which turn words construct geometry and admissible bit rewrites construct the transition graph. Global complement is an exact mirror symmetry; for a complement-stable Hamiltonian it separates the quantum space into even and odd sectors, retaining the necessary sheet sign and inverse readout. In the 12-residue HP example, 776 legal conformations form 388 mirror pairs. Classical propagation in the full Hilbert space and its independently assembled mirror-even sector agrees after reconstruction to machine precision under the reported sparse solver; the precise rounding error is implementation dependent. Local four-turn hexagon rewrites are reversible but fragment the legal graph; unrestricted pivots reconnect it while sacrificing bounded spatial support. Together these results establish a rigorous, finite compiler architecture and a precise reduction in the resources needed for symmetry-selected states. They do not establish experimentally validated molecular kinetics, a general quantum-simulation speedup, or measured low electrical power. The remaining link is an independently constrained molecular transition generator, its environmental coupling, and a resource benchmark carried out under the same input–output contract. Keywords: NEXUS; reversible routing; quantum-inspired classical simulation; parity decomposition; Hilbert-space reduction; self-avoiding walks; hydrophobic-polar models; constrained transitions; local moves; protein folding. Figure 1. The integrated compiler path: binary word → geometric legality → admissible transition graph → symmetry sectors → classical propagation. The route back to full state is explicit. PART I / THE NATIVE STATE SPACE AND WHAT “QUANTUM COMPILER” MEANS 1. Problem statement: computation before hardware The motivating hypothesis is that a sufficiently explicit mathematical relation space can execute useful quantum-style calculations on conventional, low-power hardware. In its strongest form, this would make special-purpose quantum machines unnecessary for the targeted tasks. A physically meaningful version of that hypothesis must distinguish three different propositions: an algebraic operator can be represented classically; a specified quantum evolution can be simulated faithfully; and the simulation has an advantageous cost in time, memory, or joules. The first two are demonstrated here in a finite structured family. The third remains subject to benchmarking. The Nexus program approaches problems from legal transformations and their return paths rather than from cataloged answers. Earlier One Inverter and twisted-partner-ring work constructed involutions, native addresses, temporal center reads, and odd-lane locks [1, 2]. The honeycomb extensions (§§144–146) supply a particularly instructive domain: a word is a conformation-generating route, while a molecular move is determined by geometry rather than by neighboring values in an address table [2]. Classical simulation of quantum subfamilies is established mathematical territory. Stabilizer circuits admit efficient classical simulation [6], and quantum-inspired linear algebra can dequantize some low-rank algorithms under explicit data-access assumptions [7, 8]. The point of the present work is narrower: show where the Nexus native-route and reflection machinery gives a concrete geometry-respecting Hilbert-space reduction, with complete return information and negative controls. The governing research hypothesis is stronger than an indexing engine. The compiler is proposed as a transformation architecture: a molecular sequence and surroundings determine lawful continuations, and a fold is the realized trajectory rather than a catalog match. The scientific question is whether a native, local, reversible transformation system reproduces a molecular process without placing the answer in a chosen transition matrix. Three different “one answer” statements must remain typed. A fully specified deterministic calculation has one result. A fully specified quantum experiment has a definite predicted probability distribution but may have multiple measurement outcomes. A protein may have an ensemble of conformations that changes with conditions. The route does not license substituting one for the others. For this paper, “compilation” has a testable meaning: construct a state domain, certify lawful transformations, select a representation that makes required relations visible, propagate that declared operator, and preserve an inverse or a residual route. Classical hardware is sufficient to carry out these finite algebraic steps. Whether it is efficient for an enlarging family depends on the structure of that family, not on a claim that all quantum amplitudes can be recovered from one address. 2. Native ring: partner, face, canonical address, and exact return For an n-bit word, J is bit reversal and C is bitwise complement. Define P(x)=J(x) unless x is palindromic, in which case P(x)=C(x). P²=I, P has no fixed word, and the native ring pairs addresses antipodally: PTP=T⁻¹, where T is the ring’s own successor. The inward E/G route ends at width two, retaining each branch and middle qualifier and a face bit. The complete code is n bits for an n-bit word; reconstruction is exact but not generic compression. P(x) = J(x) if J(x) ≠ x; P(x) = C(x) otherwise. The canonical address is an exact re-labeling of word space. T is a native address successor. A raw k-bit transport shift, a partner read, and T are separate operators. In particular, declaring an edge between successive catalog addresses does not establish that the corresponding conformations are molecular neighbors. Three interfaces must not be conflated. The native ring successor T is a step in canonical address order. The geometric word rewrite is a change of chain conformation. A measurement/readout R extracts a specified property of the state. In particular, T does not become a protein move simply because it is a reversible permutation. The twisted one-inverter clock and temporal reader The “One Inverter” paper derives the affine twisted rotation τ(x₀…xₙ₋₁)=x₁…xₙ₋₁¬x₀, so after k ticks the first k departing bits are returned complemented. At k=n it is global complement; at k=2n the state returns. The inward terminal reader is exactly the XOR of the two central word bits. Under τ, its temporal trace reads each adjacent difference around the cyclic word, with one known inverted crossing. τᵏ(x) = rotlₖ(x) ⊕ (2ᵏ − 1), 0 ≤ k ≤ n; τⁿ = C, τ²ⁿ = I. r(x) = xₙ/₂₋₁ ⊕ xₙ/₂ ; ⊕ₜ₌₀ⁿ⁻¹ r(τᵗ x) = 1. [even n] The n−1 independent adjacent differences plus one native face bit recover the word. The two-bit closed complement-feedback rule is τ², not a new primitive. None of this creates a physical molecule; it gives a provably executable, invertible substrate for how a local reader can obtain and return distinctions. Odd-lane locks and relational deviations For odd q and n=qs, the alternating-complement lift Λq(u)=u‖Cu‖u‖…‖u is invariant under the twisted clock and intertwines J, C, and P. A center trace of period s identifies this lock and supports exact reconstruction through the first s-bit lane. In the full q-lane state, de-staggered lane differences and one anchor preserve all n bits. τₙ Λq = Λq τₛ ; Pₙ Λq = Λq Pₛ ; dH(Λq u,Λq v) = q · dH(u,v). These differences were formerly called “defects.” They are lawful relational deviations from a selected lock—not failures of the transformation. Under common affine transport, differences rotate and preserve weight. An external input can alter them at a known boundary, but selecting an input law is not already derived by the native permutation. The native address T, the twisted clock τ, and the geometric pivot defined later remain separate typed operators. The exact E/G route has n bits for a general n-bit input. A locked multi-lane family instead requires only its independent local state and the stated lift rule; the reduction comes from a demonstrated invariant restriction, not from labeling an arbitrary large input “locked.” Which operations the embedding preserves The One Inverter temporal read is an operational return path, not just a yes/no label. For n=2h, define the cyclic adjacent differences Dᵢ=xᵢ⊕xᵢ₊₁ (indices modulo n) and the observed center trace yₜ=r(τᵗx). The twisted boundary contributes exactly one inverted crossing. Over n ticks the center presents n relations; their XOR equals one, and n−1 of them together with the retained canonical face bit reconstruct the entire original word. The E/G inward/outward route supplies a separate exact return by retained qualifiers. Neither return is compression of arbitrary n-bit words. yₜ = D₍ₕ₋₁₊ₜ₎ mod n ⊕ [t=h], ⊕ₜ₌₀ⁿ⁻¹ yₜ = 1; (y₀,…,yₙ₋₂, face) ↔ x. The two masks must not be conflated. The mirror shell lamps are gⱼ=xⱼ⊕xₙ₋₁₋ⱼ, the paired entries in x⊕J(x). The dist