Quantum Reports, Volume 8, Issue 3

Restricting the $\left[[3L^3,2L^3+2,3]\right]$ FCC lattice code to a single triad sheet gives the $\left[[L^3,2L,L]\right]$ sheet code, with uniform weight-4 stabilizers and $K=4$ active connectivity. This code is isomorphic to L disjoint rotated 2D toric codes, so its memory is t...

The three triad sheets of the face-centered cubic (FCC) lattice, at even lattice size L, are edge-disjoint but share their vertex and octahedral-void ancilla positions. Running the three sheet codes in a three-round time-multiplexed cycle on one chip...

We extend our description of the electron’s quaternion spin (Q–spin) as a geometric rotor. This follows from incorporating both the symmetric polarization and the antisymmetric coherence into the theory. Polarization is observed only thro...

We review recent calculations and numerical simulations showing the formation of coherent states of protons in hydrogen-loaded metals with a cubic crystal lattice. The characteristic frequencies discussed here are the local proton frequency, the plas...

Network delays are correlated, so treating hub airports as independent can severely understate simultaneous delay events. This study formulates system-wide flight-delay scenario generation with a pure-state quantum circuit Born machine (QCBM), in whi...

Hardware noise and finite sampling perturb the fidelity estimates forming a quantum-kernel Gram matrix. We measured how far three hardware-reconstructed Gram matrices depart from an exact statevector reference for one frozen four-qubit ZZ feature map...

Optimization problems in machine-learning (ML) applications can be computationally challenging for classical methods, particularly when they involve large, unstructured search spaces. Quantum computing offers a promising approach to combinatorial opt...

Discrete-Variable Quantum Key Distribution (DV-QKD) provides a mechanism for establishing secret keys between legitimate parties using quantum-state transmission and authenticated classical post-processing. In this work, the underlying quantum layer...

The island formula recovers a unitary Page curve in controlled gravitational models, but the dominance of an island saddle, the existence of a radiation recovery channel, and the cost of implementing that channel are logically distinct statements. We...

In the Selection-Stitch Model (SSM), baryonic matter is a $K=4$ remnant trapped in a tetrahedral void of the $K=12$ FCC vacuum lattice. We examine the second interstitial site, the octahedral void, as a candidate dark matter trap. Its bonded subgraph is...

A system with two periodic directions carries two commuting holonomies $a=(u,v)\in {\mathbb{R}}^2/{\mathbb{Z}}^2$. We determine their distinguished values while separating lattice, arithmetic, and observable effects. Maximizing the lowest twisted eigenvalue places a at a de...

The integer quantum Hall effect (IQHE), Z₂ topological insulators (TIs), and quantum capacitance are generally treated as separate subjects, yet they share a common thread: bulk topology gives rise to a protected boundary state, and quantum capacitan...

Physics describes evolution, causal structure, and measurement outcomes, but lacks an accepted physical account of why one outcome-conditioned quantum situation is actual as the present. This article develops a conditional account within the reconstr...

This paper develops a Holographic Bit–Mode Balance (HBMB) regularization scheme for Wheeler–DeWitt cosmology. A concrete flat-FLRW plus free-scalar clock background is first deparametrized and only then split into accessible and omitted s...

The formulation of Quantum Field Theory (QFT) in phase space offers a unique alternative to operator and path-integral paradigms, providing distinct conceptual advantages for semiclassical expansions. In this work, we present a systematic and self-co...

Entropy has evolved from a secondary thermodynamic property (Clausius, 1865) to a potentially fundamental organizing structure of physical reality, particularly through its gravitational manifestation in the Bekenstein–Hawking formula. This art...

Recently, a publication has appeared that supports the common belief that Einstein’s Equivalence Principle survives for both classical and quantum composite bodies. In contrast, we show that although it holds for classical composite bodies, the...

I estimate the size of expected Born rule violation for a two-level superconducting qubit with dispersive readout. The estimate is based on extrapolating from an earlier analysis of experimental data on cloud chamber detection. That analysis made no...

The classical Gupta–Bleuler quantization scheme in quantum electromagnetic field theory, based on the so-called “weakened” Lorenz subsidiary condition and indefinite metric on the reduced Fock space, is revisited within the context...

The synthesis of efficient reversible logic circuits is critical for fault-tolerant quantum computing (FTQC). The primary motivation of this work is to overcome the inherent disadvantages of existing synthesis techniques: approximate heuristic method...

We model the vacuum as a discrete face-centered-cubic ($K=12$) tensor network with Bell-pair bonds and use it to predict a two-step quantum-to-classical threshold for macroscopic center-of-mass superpositions. A reversible dispersive deformation of the...

The counter-diabatic shortcut to adiabaticity (CDSTA) has been explored in implementing qudit quantum Fourier transforms (QFTs) via stimulated Raman adiabatic passage (STIRAP) to suppress non-adiabatic leakage. While direct CD driving may introduce u...

A smooth window function $♢\left(x\right)\in [0,1]$ that restricts a field-theory action to a finite spacetime domain generates a common conservation structure across diverse experimentally realized finite-time quantum phenomena. Applying the windowed act...

The quantum–classical transition is one of the most frequently invoked concepts in modern physics. Yet the notion of classicality itself is far from unique. Depending on the physical context, classical behavior may be associated with decoherenc...

High-fidelity two-qubit entangling gates are essential for the realization of useful quantum algorithms on quantum processors. The Mølmer–Sørensen (MS) gate has become a common choice for trapped-ion quantum computing due to its r...

The minimum accuracy heuristic provides a training-free way to evaluate quantum feature maps, but its original formulation assumes balanced datasets, requires an exhaustive Pauli-axis scan, and lacks a formal lower-bound interpretation. In this work,...

Understanding whether the mathematical structure of quantum mechanics is fundamental or emergent remains a central question in the foundations of physics. In particular, the special role played by time in quantum theory, appearing as an external evol...

We derive the reduced-spin von Neumann entropy generated by unitary Stern–Gerlach spin–position entanglement in a closed system. For any pure two-branch state with normalized spatial branches, the reduced-spin spectrum and entropy are det...

The charged-lepton pole masses exhibit the well-known Koide relation, in which the square-root geometry reduces the three-mass pattern to a one-angle problem. This paper first gives a self-contained algebraic formulation of that geometry: the Koide c...

Rapid progress in quantum computing threatens the long-term security of classical cryptographic primitives, and with them the integrity of contemporary blockchain systems that rely fundamentally on computational hardness assumptions. Hence, quantum-n...

Three results. (1) We prove the tensor-level conformal identity $d{s}_{\mathrm{BK}}^2=4{\gamma }^2\left(r\right) d{s}_{\mathrm{Bures}}^2$ between the Bures metric and the Beltrami–Klein metric on the open qubit Bloch ball, where ${\gamma }^2\left(r\right)=1/(1-r^2)$ is the squared Lorentz factor...

We address the problem of determining whether a given mixed quantum state corresponds to thermal equilibrium or to a zero-temperature statistical mixture. We show that geometric observables, in particular the quantum Fisher information, provide a dir...

The quantum measurement problem separates into operational questions: which observables are stable records, how outcome probabilities are represented, how conditional post-event states are updated, and how a detector event time is assigned. We give a...

This paper re-examines quantum tunnelling—the penetration of a potential barrier by a subatomic particle—through the lens of classical wave dynamics. The author contends that applying the standard Schrödinger equation to this phenome...

Nucleic acids exhibit structured electromagnetic features shaped by classical electronegativity (EN) patterns. Mapping Pauling EN values across DNA and RNA reveals a largely invariant, high-EN phosphodiester backbone that provides a consistent electr...

The central charge occupies a unique role in conformal field theory, simultaneously serving as a measure of degrees of freedom, as the determinant of Casimir energy through modular transformations, and as an obstruction to the naive extension of the...

We introduce the Hamiltonian pseudorandom function (HPRF), a new symmetric cryptographic primitive in which the function family $\left\{F_k\right\}$ is defined by $F_k\left(q\right)=\nabla S_k\left(q\right)$, the gradient of the generating function of a secret Lagrangian submanifold $L_k$ on th...

We characterize when exponential reweightings of a no-signalling CHSH probability box preserve no-signalling. While such tilts are automatically positive and normalized within each measurement setting, they can modify cross-setting marginals and ther...

The Rio Santiago basin is one of the most environmentally stressed river systems in Mexico, with persistent organic, nutrient, microbial, surfactant, and metal contamination. This study develops a near-term quantum machine learning workflow for envir...

We propose a foundational framework in which internal temporal ordering, the low-entropy boundary of the observable branch, the compatibility of a local thermodynamic arrow with a global partition lifecycle, and a qualitative late-time dark-energy si...

Lead isotope ratios are frequently used in archaeometric provenance analysis; however, the overlap of isotopic fields within the Andean metallogenic belt complicates reliable provenance determination. This study presents a reproducible fidelity-based...

We thank Vrba for the careful and constructive analysis of bivector spin [...]