Papers
Non-Gaussianity from superselection rules
Nicolas Moulonguet, Eloi Descamps, José Lorgeré +3 more·Mar 21, 2026
The quantum theory of the electromagnetic field enables the description of multiphoton states exhibiting nonclassical statistical properties, often reflected in non-Gaussian phase-space distributions. While non-Gaussianity alone does not fully charac...
Geometric Diagnostics of Scrambling-Related Sensitivity in a Bohmian Preparation Space
Stephen Wiggins·Mar 21, 2026
The Out-of-Time-Order Correlator (OTOC) is a standard algebraic diagnostic of quantum information scrambling, but it offers limited direct geometric intuition. In this note, we propose a Bohmian, trajectory-based framework for constructing a geometri...
A Phase-Space Geometric Measure of Magic in Qubit Systems
Soumyojyoti Dutta, Tushar·Mar 21, 2026
Characterizing quantum magic -- the resource enabling computational advantage beyond stabilizer circuits -- is subtle in qubit systems because established measures can give conflicting information about the same state. We introduce C(rho), the l1 dis...
Simultaneous Detection of High-Dimensional Entanglement for Two Unknown Quantum States
Mao-Sheng Li, Chang-Yue Zhang, Zheng Zheng +7 more·Mar 21, 2026
The state overlap, quantified via $\tr[ρσ]$, is a metric widely used to assess the closeness between two quantum states $ρ$ and $σ$. Although global state overlap alone does not directly capture entanglement properties, we uncover that incorporating ...
Temporal Entanglement in Quantum Field Theory
Olalla A. Castro-Alvaredo·Mar 21, 2026
In this paper I propose a branch point twist field approach to computing a temporal entropy, that is, an entanglement measure across different time regions, as opposed to the usual spacial measures. I discuss how the shift to time-dependence manifest...
Asymptotic statistical theory of irreducible quantum Markov chains
Federico Girotti, Jukka Kiukas, Mădălin Guţă·Mar 21, 2026
In this paper we investigate the asymptotic statistical theory of irreducible quantum Markov chains, focusing on identifiability properties and asymptotic convergence of associated quantum statistical models. We show that the space of identifiable pa...
Practical advantage of non-Hermitian enhanced quantum sensing
Kun Yang, Yaoming Chu, Ning Wang +1 more·Mar 21, 2026
Non-Hermitian systems have emerged as a powerful paradigm for ultrasensitive sensing, leveraging unique spectral and dynamical properties that find no counterparts in Hermitian physics. While recent theoretical assessments have established that these...
Empirical Falsification of Pairwise-Only Explanations for an Engineered Parity Benchmark on a 133-Qubit Superconducting Processor
Petr Sramek·Mar 20, 2026
Scalable quantum characterization and error-mitigation workflows often rely on the assumption that relevant device noise and readout contamination can be adequately captured by low-weight, predominantly pairwise interactions. We report a compact hard...
Quantum Entanglement Assistance Improves the Capacity and Activates the Zero-Error Capacity of Classical Channels with Causal CSIT
Yuhang Yao, Syed A. Jafar·Mar 20, 2026
For classical point-to-point channels, it has been shown by Bennett et al. that quantum entanglement assistance cannot improve their capacity, and by Cubitt et al. that entanglement assistance cannot activate (increase from zero to non-zero) their ze...
Error-Correction Transitions in Finite-Depth Quantum Channels
Arman Sauliere, Guglielmo Lami, Pedro Ribeiro +2 more·Mar 20, 2026
We study error correction type protocols in which a quantum channel encodes logical information into an enlarged Hilbert space. Specifically, we consider channels realized by one dimensional random noisy quantum circuits with spatially local interact...
Heisenberg-scaling characterization of an arbitrary two-channel network via two-port homodyne detection
Atmadev Rai, Paolo Facchi, Vincenzo Tamma·Mar 20, 2026
We present a fully Gaussian and experimentally feasible scheme for the simultaneous estimation of the four real parameters that characterize an arbitrary two-channel unitary transformation. The scheme utilizes a two-mode squeezed probe and balanced h...
Analyzing Decoders for Quantum Error Correction
Abtin Molavi, Feras Saad, Aws Albarghouthi·Mar 20, 2026
Quantum error correction (QEC) enables reliable computation on noisy hardware by encoding logical information across many physical qubits and periodically measuring parities to detect errors. A decoder is the classical algorithm that uses these measu...
A single programmable photonic circuit for universal quantum measurements
Wen-Zhe Yan, Lan-Tian Feng, Zhibo Hou +7 more·Mar 20, 2026
Programmable photonic quantum processors face a critical challenge: despite significant advances in quantum state preparation and manipulation, measurements remain limited to projective techniques. Here, we demonstrate a programmable measurement proc...
Variance reduction methods in the estimation of Pauli sums
Søren Fuglede Jørgensen, Rafael Emilio Barfknecht, Patrick Ettenhuber +1 more·Mar 20, 2026
Accurately estimating expectation values of quantum observables with as few measurements as possible is crucial to many quantum computing applications. We introduce a framework that covers many of existing measurement strategies and introduce heurist...
Cryptanalysis of four arbitrated quantum signature schemes
Pierre-Alain Jacqmin, Jean Liénardy·Mar 20, 2026
Arbitrated quantum signature (AQS) schemes aim at ensuring the authenticity of a message with the help of an arbitrator. Moreover, they aim at preventing repudiation, both from a sender that denies the origin of a message, and from a receiver who dis...
Quantum Fisher Information as a Probe of Critical Scaling in Frustrated Magnets: Signatures from Kagome Quantum Spin Liquid
Zhengbang Zhou, Chengkang Zhou, Menghan Song +2 more·Mar 20, 2026
Quantum Fisher information (QFI) is a measure of multipartite quantum entanglement that can be obtained from inelastic neutron scattering data on quantum magnets. In this work, we demonstrate that the QFI can distinguish an unconventional quantum cri...
Beyond-Ten-Hour Coherence in a Decoherence-Free Trapped-Ion Clock Qubit
Jiahao Pi, Xiangjia Liu, Junle Cao +8 more·Mar 20, 2026
Quantum systems promise to revolutionize information processing science and technology [1-3]. The preservation of quantum coherence, the defining property of qubits, fundamentally constrains the performance of quantum information processing with quan...
Vertex structure of fiber products of probability polytopes
Aziz Kharoof, Cihan Okay·Mar 19, 2026
We develop tools for characterizing vertices of fiber products of polytopes and apply them to simplicial distribution polytopes, a class of probability polytopes arising in quantum foundations and quantum information. In the theory of simplicial dist...
Approximate virtual quantum broadcasting
Matthew Simon Tan, Davit Aghamalyan, Varun Narasimhachar·Mar 19, 2026
The no-broadcasting theorem, a fundamental limitation on the communication of quantum information, holds that a physical process cannot broadcast copies of an unknown quantum state to two or more receivers. Recent work has explored ways of circumvent...
The Bilateral Efficiency of Ethernet: Recalibrating Metcalfe and Boggs After Fifty Years
Paul Borrill·Mar 19, 2026
In July 1976, Metcalfe and Boggs published their foundational paper on Ethernet in Communications of the ACM. Their efficiency model -- E = (P/C)/(P/C + W*T) -- measures the fraction of Ether time carrying good forward packets under contention. For f...