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Related papers: A priori Probabilities of Separable Quantum States

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It is well known, that the causal Schr\"odinger evolution of a quantum state is not compatible with the reduction postulate, even when decoherence is taken into account. The violation of the causal evolution, introduced by the standard…

Quantum Physics · Physics 2007-05-23 Rodolfo Gambini

In this work, we derive Robertson-Heisenberg like uncertainty relation for two incompatible observables in a pre- and post-selected (PPS) system. The newly defined standard deviation and the uncertainty relation in the PPS system have…

Quantum Physics · Physics 2024-01-05 Sahil , Sohail , Sibasish Ghosh

A precise physical description and understanding of the classical dual content of quantum theory is necessary in many disciplines today: from concepts and interpretation to quantum technologies and computation. In this paper we investigate…

Quantum Physics · Physics 2025-12-01 Diego J. Cirilo-Lombardo , Norma G. Sanchez

The optimal (pure state) ensemble length of a separable state, A, is the minimum number of (pure) product states needed in convex combination to construct A. We study the set of all separable states with optimal (pure state) ensemble length…

Quantum Physics · Physics 2015-06-26 Robert B. Lockhart

Quantum measurements are crucial to observe the properties of a quantum system, which however unavoidably perturb its state and dynamics in an irreversible way. Here we study the dynamics of a quantum system while being subject to a…

For a random quantum state on $H=C^d \otimes C^d$ obtained by partial tracing a random pure state on $H \otimes C^s$, we consider the whether it is typically separable or typically entangled. For this problem, we show the existence of a…

Quantum Physics · Physics 2015-05-12 Guillaume Aubrun , Stanislaw J. Szarek , Deping Ye

We present a quasipolynomial-time algorithm for solving the weak membership problem for the convex set of separable, i.e. non-entangled, bipartite density matrices. The algorithm decides whether a density matrix is separable or whether it…

Quantum Physics · Physics 2011-06-13 Fernando G. S. L. Brandao , Matthias Christandl , Jon Yard

We consider a Quantum Computer with n quantum-bits (`qubits'), where each qubit is coupled independently to an environment affecting the state in a dephasing or depolarizing way. For mixed states we suggest a quantification for the property…

Quantum Physics · Physics 2008-12-18 Dominik Janzing , Thomas Beth

In this paper we explore the possibility of performing Heisenberg limited quantum metrology of a phase, without any prior, by employing only maximally entangled states. Starting from the estimator introduced by Higgins et al. in New J.…

Quantum Physics · Physics 2020-10-27 Federico Belliardo , Vittorio Giovannetti

Let Alice and Bob be able to make local quantum measurements and communicate classically. The set of mathematically consistent joint probability assignments (``states'') for such measurements is properly larger than the set of…

Quantum Physics · Physics 2007-05-23 Howard Barnum , Christopher A. Fuchs , Joseph M. Renes , Alexander Wilce

We introduce a measure Q of bipartite quantum correlations for arbitrary two-qubit states, expressed as a state-independent function of the density matrix elements. The amount of quantum correlations can be quantified experimentally by…

Quantum Physics · Physics 2012-04-16 Davide Girolami , Gerardo Adesso

A quantum probability measure--or quantum measurement--is said to be clean if it cannot be irreversibly connected to any other quantum probability measure via a quantum channel. The notion of a clean quantum measure was introduced by…

Quantum Physics · Physics 2018-11-30 Douglas Farenick , Remus Floricel , Sarah Plosker

The goal of comparison is to reveal the difference of compared objects as fast and reliably as possible. In this paper we formulate and investigate the unambiguous comparison of unknown quantum measurements represented by non-degenerate…

Quantum Physics · Physics 2009-11-13 Mario Ziman , Teiko Heinosaari , Michal Sedlak

An emergent theory of quantum measurement arises directly by considering the particular subset of many body wavefunctions that can be associated with classical condensed matter and its interaction with delocalized wavefunctions. This…

Quantum Physics · Physics 2015-03-03 Clifford Chafin

Predictions for systems in entangled states cannot be described in local realistic terms. However, after admixing some noise such a description is possible. We show that for two quNits (quantum systems described by N dimensional Hilbert…

Quantum Physics · Physics 2013-05-29 Thomas Durt , Dagomir Kaszlikowski , Marek Zukowski

When two or more subsystems of a quantum system interact with each other they can become entangled. In this case the individual subsystems can no longer be described as pure quantum states. For systems with only 2 subsystems this…

Quantum Physics · Physics 2007-05-23 Rachel Parker , Chris Doran

We propose a formulation of quantum measurement within a modified framework of frames, in which a quantum system - a single qubit - is directly coupled to a classical measurement bit. The qubit is represented as a positive probability…

Quantum Physics · Physics 2025-12-04 Dagomir Kaszlikowski , Pawel Kurzynski

We consider probabilistic theories in which the most elementary system, a two-dimensional system, contains one bit of information. The bit is assumed to be contained in any complete set of mutually complementary measurements. The…

Quantum Physics · Physics 2009-07-10 Caslav Brukner , Anton Zeilinger

We demonstrate the feasibility to completely characterize entanglement by negativities of quasiprobabilities. This requires the complete solution of a sophisticated mathematical problem, the so-called separability eigenvalue problem. Its…

Quantum Physics · Physics 2015-06-05 J. Sperling , W. Vogel

A simple minimalist argument is given for why some correlations between quantum systems boggle our classical intuition. The argument relies on two elementary physical assumptions, and recovers the standard experimentally-testable Bell…

Quantum Physics · Physics 2024-08-29 Michael J. W. Hall
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