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The paper discusses progress in understanding statistical properties of complex eigenvalues (and corresponding eigenvectors) of weakly non-unitary and non-Hermitian random matrices. Ensembles of this type emerge in various physical…

Chaotic Dynamics · Physics 2009-11-07 Yan V Fyodorov , H. -J Sommers

The asymptotic quantum trajectory of weak continuous measurement for the magnetometer is investigated. The magnetometer refers to a setup where the field-to-estimate and the measured moment are orthogonal, and the quantum state is governed…

Quantum Physics · Physics 2023-11-06 Chungwei Lin , Yanting Ma , Dries Sels

Random-matrix theory is used to study the mesoscopic fluctuations of the excitation gap in a metal grain or quantum dot induced by the proximity to a superconductor. We propose that the probability distribution of the gap is a universal…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. G. Vavilov , P. W. Brouwer , V. Ambegaokar , C. W. J. Beenakker

Temporal quantum correlations provide an intriguing way of testing quantumness at the macroscopic level, with a logical hierarchy present among the quantum correlations associated with nonmacrorealism, temporal steering, and temporal…

Quantum Physics · Physics 2025-05-26 Hao-Cheng Weng , Chen-Yeh Wei , Huan-Yu Ku , Shin-Liang Chen , Yueh-Nan Chen , Chih-Sung Chuu

A new model of quantum random walks is introduced, on lattices as well as on finite graphs. These quantum random walks take into account the behavior of open quantum systems. They are the exact quantum analogues of classical Markov chains.…

Quantum Physics · Physics 2014-02-14 S. Attal , F. Petruccione , C. Sabot , I. Sinayskiy

A monitored quantum system undergoing a cyclic evolution of the parameters governing its Hamiltonian accumulates a geometric phase that depends on the quantum trajectory followed by the system on its evolution. The phase value will be…

A novel method is proposed for detecting changes in the covariance structure of moderate dimensional time series. This non-linear test statistic has a number of useful properties. Most importantly, it is independent of the underlying…

Methodology · Statistics 2021-08-18 Sean Ryan , Rebecca Killick

When transforming pairs of independent quantum operations according to the fundamental rules of quantum theory, an intriguing phenomenon emerges: some such higher-order operations may act on the input operations in an indefinite causal…

Quantum Physics · Physics 2022-02-08 Jessica Bavaresco , Mateus Araújo , Časlav Brukner , Marco Túlio Quintino

Measurements are a vital part of any quantum computation, whether as a final step to retrieve results, as an intermediate step to inform subsequent operations, or as part of the computation itself (as in measurement-based quantum…

Quantum Physics · Physics 2023-04-14 Stefanie J. Beale , Joel J. Wallman

We consider the scattering matrix approach to quantum electron transport in meso- and nano-conductors. This approach is an alternative to the more conventional kinetic equation and Green's function approaches, and often is more efficient…

Mesoscale and Nanoscale Physics · Physics 2015-04-09 G. B. Lesovik , I. A. Sadovskyy

Monitored quantum systems evolve along stochastic trajectories correlated with the observer's knowledge of the system's state. Under such dynamics, certain quantum resources like entanglement may depend on the observer's state of knowledge.…

Quantum Physics · Physics 2024-09-04 Christian Carisch , Oded Zilberberg , Alessandro Romito

We present a framework for deciding whether a quantum state is separable or entangled using covariance matrices of locally measurable observables. This leads to the covariance matrix criterion as a general separability criterion. We…

Quantum Physics · Physics 2008-12-03 Oleg Gittsovich , Otfried Gühne , Philipp Hyllus , Jens Eisert

We discuss the concept of connection states (or connection matrices) that describe posterior ensembles, post-selected according to the outcomes of a quantum measurement. Connection matrices allow one to obtain results of any weak and some…

Quantum Physics · Physics 2013-08-02 Abraham G. Kofman , Sahin K. Ozdemir , Franco Nori

Quantum mechanics predicts the existence of intrinsically random processes. Contrary to classical randomness, this lack of predictability can not be attributed to ignorance or lack of control. Here we find the optimal method to quantify the…

Quantum Physics · Physics 2015-12-07 Elsa Passaro , Daniel Cavalcanti , Paul Skrzypczyk , Antonio Acín

Ballistic quantum wires are exposed to longitudinal profiles of perpendicular magnetic fields composed of a spike (magnetic barrier) and a homogeneous part. An asymmetric magnetoconductance peak as a function of the homogeneous magnetic…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 A. Tarasov , S. Hugger , Hengyi Xu , M. Cerchez , T. Heinzel , I. V. Zozoulenko , U. Gasser-Szerer , D. Reuter , A. D. Wieck

The authors apply the generalized master equation to analyze time-dependent transport through a finite quantum wire with an embedded subsystem. The parabolic quantum wire and the leads with several subbands are described by a continuous…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Vidar Gudmundsson , Cosmin Gainar , Chi-Shung Tang , Valeriu Moldoveanu , Andrei Manolescu

A one-dimensional quantum oscillator is monitored by taking repeated position measurements. As a first con- tribution, it is shown that, under a quantum nondemolition measurement scheme applied to a system initially at the ground state, (i)…

Quantum Physics · Physics 2015-11-13 Vincenzo Matta , Vincenzo Pierro

A one-parameter random matrix model is proposed for describing the statistics of the local amplitudes and phases of electron eigenfunctions in a mesoscopic quantum dot in an arbitrary magnetic field. Comparison of the statistics obtained…

Condensed Matter · Physics 2009-10-28 E. Kanzieper , V. Freilikher

This paper treats absorption problems for the one-dimensional quantum walk determined by a 2 times 2 unitary matrix U on a state space {0,1,...,N} where N is finite or infinite by using a new path integral approach based on an orthonormal…

Quantum Physics · Physics 2009-11-07 Norio Konno , Takao Namiki , Takahiro Soshi , Aidan Sudbury

Quantification is well known to be a major obstacle in the construction of a probabilistic network, especially when relying on human experts for this purpose. The construction of a qualitative probabilistic network has been proposed as an…

Artificial Intelligence · Computer Science 2013-01-07 Silja Renooij , Linda C. van der Gaag