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We study the normal form of multipartite density matrices. It is shown that the correlation matrix (CM) separability criterion can be improved from the normal form we obtained under filtering transformations. Based on CM criterion the…

Quantum Physics · Physics 2015-05-13 Ming Li , Shao-Ming Fei , Zhi-Xi Wang

We analyse the use of entangled states to perform quantum computations non locally among distant nodes in a quantum network. The complexity associated with the generation of multiparticle entangled states is quantified in terms of the…

Quantum Physics · Physics 2009-10-31 J. I. Cirac , A. Ekert , S. F. Huelga , C. Macchiavello

The detection of entanglement in a bipartite state is a crucial issue in quantum information science. Based on realignment of density matrices and the vectorization of the reduced density matrices, we introduce a new set of separability…

Quantum Physics · Physics 2024-12-09 Yu Lu , Zhong-Xi Shen , Shao-Ming Fei , Zhi-Xi Wang

To store quantum information, quantum memory plays a central intermediate ingredient in a network. The minimal criterion for a reliable quantum memory is the maintenance of the entangled state, which can be described by the…

Quantum Physics · Physics 2023-12-13 Wan-Guan Chang , Chia-Yi Ju , Guang-Yin Chen , Yueh-Nan Chen , Huan-Yu Ku

We define the quantum-incoherent relative entropy of coherence ($\mathcal{QI}$ REC) of quantum channels in the framework of the resource theory by using the Choi-Jamiolkowsky isomorphism. Coherence-breaking channels are introduced as free…

Quantum Physics · Physics 2020-06-30 F. H. Kamin , F. T. Tabesh , S. Salimi , F. Kheirandish

Quantum state separation is a probabilistic map that transforms a given set of pure states into another set of more distinguishable ones. Here we investigate such a map acting onto uniparametric families of symmetric linearly dependent or…

Quantum Physics · Physics 2017-03-09 M. A. Solís-Prosser , A. Delgado , O. Jiménez , L. Neves

Motivated by the Kronecker product approximation technique, we have developed a very simple method to assess the inseparability of bipartite quantum systems, which is based on a realigned matrix constructed from the density matrix. For any…

Quantum Physics · Physics 2007-05-23 Kai Chen , Ling-An Wu

In this work we analyze properties of generic quantum channels in the case of large system size. We use random matrix theory and free probability to show that the distance between two independent random channels converges to a constant…

Quantum Physics · Physics 2018-07-09 Ion Nechita , Zbigniew Puchała , Łukasz Pawela , Karol Życzkowski

We analyze two ways to obtain distinguishability measures between quantum maps by employing the square root of the quantum Jensen-Shannon divergence, which forms a true distance in the space of density operators. The arising measures are…

Quantum Physics · Physics 2023-07-19 Diego G. Bussandri , Pedro W. Lamberti , Karol Życzkowski

We derive a family of necessary separability criteria for finite-dimensional systems based on inequalities for variances of observables. We show that every pure bipartite entangled state violates some of these inequalities. Furthermore, a…

Quantum Physics · Physics 2016-09-08 Otfried Guehne

Most general dynamics of an open quantum system is commonly represented by a quantum channel, which is a completely positive trace-preserving map (CPTP or Kraus map). Well-known are the representations of quantum channels by Choi matrices…

Quantum Physics · Physics 2025-06-10 Ivan Russkikh , Boris Volkov , Alexander Pechen

By combining a parameterized Hermitian matrix, the realignment matrix of the bipartite density matrix $\rho$ and the vectorization of its reduced density matrices, we present a family of separability criteria, which are stronger than the…

Quantum Physics · Physics 2015-11-03 Shu-Qian Shen , Meng-Yuan Wang , Ming Li , Shao-Ming Fei

By definition a separable state has the form \sum A_i \otimes B_i, where 0 \leq A_i, B_i for each i. In this paper we consider the class of states which admit such a decomposition with B_1, ..., B_p having independent images. We give a…

Quantum Physics · Physics 2012-02-17 Erik Alfsen , Fred Shultz

The separability from spectrum problem asks for a characterization of the eigenvalues of the bipartite mixed states {\rho} with the property that U^*{\rho}U is separable for all unitary matrices U. This problem has been solved when the…

Quantum Physics · Physics 2014-01-17 Nathaniel Johnston

By using the Choi-Jamio{\l}kowski isomorphism, we propose a well-defined coherence measure of quantum channels based on the generalized $\alpha$-$z$-relative R\'{e}nyi entropy. In addition, we present an alternative coherence measure of…

Quantum Physics · Physics 2025-06-13 Jiaorui Fan , Zhaoqi Wu , Shao-Ming Fei

We present an instance of a task of minimum-error discrimination of two qubit-qubit quantum channels for which a sequential strategy outperforms any parallel strategy. We then establish two new classes of strategies for channel…

Quantum Physics · Physics 2021-11-24 Jessica Bavaresco , Mio Murao , Marco Túlio Quintino

Errors are the fundamental barrier to the development of quantum systems. Quantum networks are complex systems formed by the interconnection of multiple components and suffer from error accumulation. Characterizing errors introduced by…

The rapid pace of recent advancements in numerical computation, notably the rise of GPU and TPU hardware accelerators, have allowed tensor network (TN) algorithms to scale to even larger quantum simulation problems, and to be employed more…

Quantum Physics · Physics 2022-09-02 Manuel S. Rudolph , Jing Chen , Jacob Miller , Atithi Acharya , Alejandro Perdomo-Ortiz

Decoherence of quantum systems is described by quantum channels. However, a complete understanding of such channels, especially in the multi-particle setting, is still an ongoing difficult task. We propose the family of quantum maps that…

We determine the minimal experimental resources that ensure a unique solution in the estimation of trace-preserving quantum channels with both direct and convex optimization methods. A convenient parametrization of the constrained set is…

Quantum Physics · Physics 2011-06-13 M. Zorzi , F. Ticozzi , A. Ferrante