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Related papers: Local asymptotic normality for qubit states

200 papers

We experimentally demonstrate the superior discrimination of separated, unentangled two-qubit correlated states using nonlocal measurements, when compared with measurements based on local operations and classical communications. When…

Quantum Physics · Physics 2008-11-26 G. J. Pryde , J. L. O'Brien , A. G. White , Stephen D. Bartlett

We investigate whether a generic multipartite pure state can be the unique asymptotic steady state of locality-constrained purely dissipative Markovian dynamics. In the simplest tripartite setting, we show that the problem is equivalent to…

Quantum Physics · Physics 2018-04-04 Salini Karuvade , Peter D. Johnson , Francesco Ticozzi , Lorenza Viola

We herein establish an asymptotic representation theorem for locally asymptotically normal quantum statistical models. This theorem enables us to study the asymptotic efficiency of quantum estimators such as quantum regular estimators and…

Quantum Physics · Physics 2024-11-14 Akio Fujiwara , Koichi Yamagata

Thermal states are the bedrock of statistical physics. Nevertheless, when and how they actually arise in closed quantum systems is not fully understood. We consider this question for systems with local Hamiltonians on finite quantum…

Quantum Physics · Physics 2017-06-22 Terry Farrelly , Fernando G. S. L. Brandao , Marcus Cramer

We discuss the problem of estimating a general (mixed) qubit state. We give the optimal guess that can be inferred from any given set of measurements. For collective measurements and for a large number $N$ of copies, we show that the error…

Quantum Physics · Physics 2009-11-10 E. Bagan , M. Baig , R. Munoz-Tapia , A. Rodriguez

We consider discrete spectra of bound states for non-relativistic motion in attractive potentials V_{\sigma}(x) = -|V_{0}| |x|^{-\sigma}, 0 < \sigma \leq 2. For these potentials the quasiclassical approximation for n -> \infty predicts…

Mathematical Physics · Physics 2011-01-06 K. Gorska , K. A. Penson , A. Horzela , G. H. E. Duchamp , P. Blasiak , A. I. Solomon

Entanglement types of pure states of 3 qubits are classified by means of their stabilisers in the group of local unitary operations. It is shown that the stabiliser is generically discrete, and that a larger stabiliser indicates a…

Quantum Physics · Physics 2009-11-06 H A Carteret , A Sudbery

Local quantum uncertainty captures purely quantum correlations excluding their classical counterpart. This measure is quantum discord type, however with the advantage that there is no need to carry out the complicated optimization procedure…

Quantum Physics · Physics 2020-09-29 Mazhar Ali

The locality of thermal quantum states has emerged as a key input for applications to thermalization, response theory, and efficient simulability. Locality is either captured by the decay of correlations or by local indistinguishability,…

Mathematical Physics · Physics 2026-01-22 Arka Adhikari , Joscha Henheik , Marius Lemm , Tom Wessel

The observation of the non-local properties of multipartite entangled states is of great importance for quantum information protocols. Such properties, however, are fragile and may not be observed in the presence of decoherence exhibited by…

Quantum Physics · Physics 2015-02-27 A. Sohbi , I. Zaquine , E. Diamanti , D. Markham

In this work, we study the dynamics of quantum coherence (total coherence, global coherence and local coherence) evolving under a local PT-symmetric Hamiltonian in maximally entangled bipartite and tripartite states. Our results indicate…

Quantum Physics · Physics 2024-11-07 Akanksha Gautam , Kavita Dorai , Arvind

When the strength of interaction between a quantum system and bath is non-negligible, the equilibrium state can deviate from the Gibbs state. But the expression of such a mean force Gibbs state in an arbitrary parameter regime is unknown…

Quantum Physics · Physics 2025-08-27 Prem Kumar

Learning the Hamiltonian underlying a quantum many-body system in thermal equilibrium is a fundamental task in quantum learning theory and experimental sciences. To learn the Gibbs state of local Hamiltonians at any inverse temperature…

Quantum Physics · Physics 2025-04-04 Chi-Fang Chen , Anurag Anshu , Quynh T. Nguyen

The unique entanglement measure is concurrence in a 2-qubit pure state. The maximum violation of Bell's inequality is monotonically increasing for this quantity. Therefore, people expect that pure state entanglement is relevant to the…

Quantum Physics · Physics 2022-12-14 Xingyu Guo , Chen-Te Ma

Quantum state discrimination involves identifying a given state out of a set of possible states. When the states are mutually orthogonal, perfect state discrimination is always possible using a global measurement. In the case of…

Quantum Physics · Physics 2023-09-13 Scott M. Cohen

We study bipartite spin-singlet correlations when rotational symmetry is described by a quantum group rather than an ordinary Lie group. We show that, even though the single-spin observables act as in the undeformed theory, the non-trivial…

Quantum Physics · Physics 2026-03-10 Michele Arzano , Goffredo Chirco , Jerzy Kowalski-Glikman

We consider the question of asymptotic stability of quantum trajectories undergoing quantum non-demolition imperfect measurement, that is to say the convergence of the estimated trajectory towards the true trajectory whose parameters and…

Quantum Physics · Physics 2023-04-06 Maël Bompais , Nina H. Amini

We combine traditional pointer-based simultaneous measurements of conjugate observables with the concept of quantum Brownian motion of multipartite systems to phenomenologically model simultaneous measurements of conjugate observables in a…

Quantum Physics · Physics 2014-05-14 Raoul Heese , Matthias Freyberger

Non-local properties of symmetric two-qubit states are quantified in terms of a complete set of entanglement invariants. We prove that negative values of some of the invariants are signatures of quantum entanglement. This leads us to…

Quantum Physics · Physics 2007-05-23 A. R. Usha Devi , M. S. Uma , R. Prabhu , Sudha

Entanglement is an useful resource because some global operations cannot be locally implemented using classical communication. We prove a number of results about what is and is not locally possible. We focus on orthogonal states, which can…

Quantum Physics · Physics 2009-11-07 Jonathan Walgate , Lucien Hardy