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One drawback of conventional quantum state tomography is that it does not readily provide access to single density matrix elements, since it requires a global reconstruction. Here we experimentally demonstrate a scheme that can be used to…

Quantum Physics · Physics 2016-09-13 G. S. Thekkadath , L. Giner , Y. Chalich , M. J. Horton , J. Banker , J. S. Lundeen

The spectral density of various ensembles of sparse symmetric random matrices is analyzed using the cavity method. We consider two cases: matrices whose associated graphs are locally tree-like, and sparse covariance matrices. We derive a…

Disordered Systems and Neural Networks · Physics 2009-11-13 Tim Rogers , Koujin Takeda , Isaac Pérez Castillo , Reimer Kühn

Indeterminacy associated with probing of a quantum state is commonly expressed through spectral distances (metric) featured in the outcomes of repeated experiments. Here we express it as an effective amount (measure) of distinct outcomes…

Quantum Physics · Physics 2021-09-21 Ivan Horváth

We discuss the decay rates of chaotic quantum systems coupled to noise. We model both the Hamiltonian and the system-noise coupling by random $N \times N$ Hermitian matrices, and study the spectral properties of the resulting Lindblad…

Quantum Physics · Physics 2019-12-11 Tankut Can , Vadim Oganesyan , Dror Orgad , Sarang Gopalakrishnan

We present the density matrix approach for theoretical description of an asymmetric double quantum dot(QD)system.The results show that the properties of gain,absorption and dispersion of the double QD system ,the population of the state…

Quantum Physics · Physics 2024-03-20 Shun-Cai Zhao , Zheng-Dong Liu

We revisit the derivation of the density of states of sparse random matrices. We derive a recursion relation that allows one to compute the spectrum of the matrix of incidence for finite trees that determines completely the low…

Condensed Matter · Physics 2009-11-07 Guilhem Semerjian , Leticia F. Cugliandolo

Distances between probability distributions are a key component of many statistical machine learning tasks, from two-sample testing to generative modeling, among others. We introduce a novel distance between measures that compares them…

Machine Learning · Statistics 2025-07-09 Arturo Castellanos , Anna Korba , Pavlo Mozharovskyi , Hicham Janati

We derive a bound on the precision of state estimation for finite dimensional quantum systems and prove its attainability in the generic case where the spectrum is non-degenerate. Our results hold under an assumption called local asymptotic…

Quantum Physics · Physics 2019-05-09 Yuxiang Yang , Giulio Chiribella , Masahito Hayashi

Suppose you receive a sequence of qubits where each qubit is guaranteed to be in one of two pure states, but you do not know what those states are. Your task is to determine the states. This can be viewed as a kind of quantum state learning…

We compute exact asymptotic of the statistical density of random matrices belonging to invariant random matrices ensemble (RMT) orthogonal, unitary and symplectic ensembles, where all its eigenvalues lie within the interval $[\sigma,…

Probability · Mathematics 2015-09-23 Mohamed Bouali

We reexamine basic aspects of a nonequilibrium steady state in the Kondo problem for a quantum dot under a bias voltage using a reduced density matrix, which is obtained in the Fock space by integrating out one of the two conduction…

Strongly Correlated Electrons · Physics 2015-06-25 Akira Oguri

Cooperative spectrum sensing based on the limiting eigenvalue ratio of the covariance matrix offers superior detection performance and overcomes the noise uncertainty problem. While an exact expression exists, it is complex and multiple…

Signal Processing · Electrical Eng. & Systems 2019-09-04 Fuhui Zhou , Norman C. Beaulieu

We discuss an alternative to relative entropy as a measure of distance between mixed quantum states. The proposed quantity is an extension to the realm of quantum theory of the Jensen-Shannon divergence (JSD) between probability…

Quantum Physics · Physics 2009-11-11 A. P. Majtey , P. W. Lamberti , D. P. Prato

In the fields of quantum mechanics and quantum information science, the traces of reduced density matrix powers play a crucial role in the study of quantum systems and have numerous important applications. In this paper, we propose a…

Quantum Physics · Physics 2025-07-24 Rui-Qi Zhang , Xiao-Qi Liu , Jing Wang , Ming Li , Shu-Qian Shen , Shao-Ming Fei

Randomization of quantum states is the quantum analogue of the classical one-time pad. We present an improved, efficient construction of an approximately randomizing map that uses O(d/epsilon^2) Pauli operators to map any d-dimensional…

Quantum Physics · Physics 2018-03-22 Paul A. Dickinson , Ashwin Nayak

We study the time dynamics of random density matrices generated by evolving the same pure state using a Gaussian orthogonal ensemble (GOE) of Hamiltonians. We show that the spectral statistics of the resulting mixed state is well described…

We study the spectral properties of a class of random matrices where the matrix elements depend exponentially on the distance between uniformly and randomly distributed points. This model arises naturally in various physical contexts, such…

Disordered Systems and Neural Networks · Physics 2015-05-18 Ariel Amir , Yuval Oreg , Yoseph Imry

We consider the distinguishability of Gaussian states from the view point of continuous-variable quantum cryptography using post-selection. Specifically, we use the probability of error to distinguish between two pure coherent (squeezed)…

Quantum Physics · Physics 2015-05-13 Christian Weedbrook , Daniel J. Alton , Thomas Symul , Ping Koy Lam , Timothy C. Ralph

We introduce with geometric means a density matrix decomposition of a multipartite quantum system of a finite dimension into two density matrices: a separable one, also known as the best separable approximation, and an essentially entangled…

Quantum Physics · Physics 2015-10-28 V. M. Akulin , G. A. Kabatyanski , A. Mandilara

The study of dissipation and decoherence in generic open quantum systems recently led to the investigation of spectral and steady-state properties of random Lindbladian dynamics. A natural question is then how realistic and universal those…

Statistical Mechanics · Physics 2020-10-22 Lucas Sá , Pedro Ribeiro , Tankut Can , Tomaž Prosen