Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.32733

Entanglement Asymmetry and Asymmetry Contour under Boundary Symmetry Breaking

Takahiro Orito·Daisuke Yamamoto
View original source ↗Read source document ↗Export metadata ↓

Abstract

We investigate how symmetry-breaking boundary magnetic fields affect magnetization and Rényi-2 entanglement asymmetry (EA) in the transverse-field Ising model. For the ground state, magnetization exhibits qualitatively distinct behaviors in the ordered and disordered phases. EA also exhibits phase-dependent behavior, which is well captured by the lower and upper bounds derived in this work. In the critical regime, both magnetization and EA exhibit behavior qualitatively consistent with the field-theoretical predictions for a related setup. We also study boundary-quench dynamics and find that magnetization propagates from the boundary into the bulk with a velocity consistent with the maximum quasiparticle velocity. In contrast, because EA is a subsystem-integrated quantity, its spatial structure is not directly resolved. We therefore introduce the asymmetry contour, a contour-like finite-difference quantity that provides a spatially resolved characterization of the symmetry-breaking information encoded in the reduced density matrix. The resulting contour is complementary to the local magnetization, retaining sensitivity to nonlocal many-body correlations while its dynamics also reflects the underlying quasiparticle propagation. These results show how EA and its contour can provide complementary information-theoretic characterizations of symmetry breaking and its spatial structure.

Explore related subjects

quant-phcond-mat.stat-mech

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Takahiro Orito, Daisuke Yamamoto. 2026-10-23. Entanglement Asymmetry and Asymmetry Contour under Boundary Symmetry Breaking. https://arxiv.org/abs/2610.32733

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Conditional Motional Squeezing of an Optomechanical Oscillator Approaching the Quantum Regime

Squeezed mechanical states are a highly coveted resource for quantum-enhanced sensing and serve as a compelling platform for probing the interplay between gravity and quantum mechanics. It has been predicted that a mechanical oscillator can be prepared into a quantum squeezed state if the applied measurement rate is fast relative to its mechanical resonance frequency. However, the experimental feasibility of this protocol has remained uncertain because of the difficulty in achieving low-frequency oscillators with sufficiently strong read-out. Here, we demonstrate that a careful selection of parameters in an optomechanical system, combined with optimal filtering techniques, enables the preparation of a 50 ng GaAs cantilever in a conditional classical squeezed state, achieving a minimum uncertainty of just 1.07 plus/minus 0.04 times the zero-point fluctuation level. This minimum variance is 3 orders of magnitude smaller than what has been achieved in previous experiments using the same protocol. Although we do not fully achieve the quantum squeezed regime, our demonstration provides definitive evidence that a measurement-based protocol is a practical and effective approach for the real-time preparation of macroscopic oscillators in quantum squeezed states.

quant-ph↗
arXiv2026

Quantum Counting in the Rydberg Blockade

We propose a quantum algorithm for approximately counting the number of solutions to planar 2-satisfiability (2SAT) formulas natively on neutral-atom quantum computers (NAQC). Our algorithm maps Boolean variables to atomic registers arranged in space according to a given formula, so that 2SAT constraints are enforced via the Rydberg blockade between neighboring atoms. A quench of an initial computational basis state then produces a superposition of all solutions after sufficiently long evolution. For almost uniform superpositions, a polynomial number of measurements is enough to estimate the solution count up to any constant multiplicative factor via sampling-based counting. Numerical simulations show that the protocol leads to almost uniform solution sampling in 1D and 2D grids and produces accurate counts for small random 2SAT instances on punctured grids. We implement our algorithm on Pasqal's Orion Alpha NAQC and demonstrate approximate counts within small multiplicative factors of the exact count for a planar grid instance with 81 atoms.

quant-ph↗
arXiv2026

Proofs of Quantum Memory

In this paper, we introduce a new concept, proofs of quantum memory (PoQM). A PoQM is an interactive protocol between a classical verifier and a quantum prover over a classical channel where the verifier can verify that the prover has possessed a specified number of qubits for a specified period of time. PoQM generalize proofs of quantumness (PoQ) [Brakerski, Christiano, Mahadev, Vazirani, and Vidick, JACM 2021] where a classical verifier can verify that the prover is not classical. Our contributions are summarized as follows: We introduce PoQM. We also introduce a variant of PoQM, which we call inefficient-verifier PoQM (IV-PoQM), where the verifier's final computation to make the decision is not necessarily efficient. We construct PoQM based on the hardness of LWE. Specifically, we give two constructions of PoQM. The first one is of two-round and has negligible soundness error under the subexponential-hardness of LWE. The second one is of polynomial-round and has inverse-polynomial soundness error under the polynomial-hardness of LWE. We show that IV-PoQM imply one-way puzzles. Moreover, we show that a certain restricted version of PoQM implies quantum computation classical communication key exchange, which suggests the difficulty of black-box constructing PoQM from one-way functions. We show that constant-round PoQ imply PoQM or single-round PoQ (with a quantum verifier). Single-round PoQ are ``trivial'' PoQ in the sense that the verifier asks the prover to solve a classical problem which is quantumly easy but classically hard. The result therefore demonstrates that PoQM capture ``genuinely-interactive'' PoQ. We show that if constant-round IV-PoQ that are black-box constructed from quantumly-secure falsifiable assumptions exist then IV-PoQM exist. This result implies that IV-PoQM can be constructed from quantumly-secure constant-round statistically-hiding commitments.

quant-ph↗