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Related papers: Solutions for the MaxEnt problem with symmetry con…

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We revisit the classical problem of inverting dimension-reducing linear mappings using the maximum entropy (MaxEnt) criterion. In the literature, solutions are problem-dependent, inconsistent, and use different entropy measures. We propose…

Machine Learning · Computer Science 2024-07-22 Paul M Baggenstoss

In this paper, we discuss the problem of determining whether a quantum system is in a pure state, or in a mixed state. We apply two strategies to settle this problem: the unambiguous discrimination and the maximum confidence discrimination.…

Quantum Physics · Physics 2009-11-13 Chi Zhang , Guoming Wang , Mingsheng Ying

This paper considers mathematical programs, whose constraints are expressed by a parameterized vector equilibrium problem. The latter is a well recognized framework, which is able to cover multicriteria optimization, vector variational…

Optimization and Control · Mathematics 2022-10-18 Amos Uderzo

We derive an analytical expression for the lower bound of the concurrence of mixed quantum states of composite 2xK systems. In contrast to other, implicitly defined entanglement measures, the numerical evaluation of our bound is…

Quantum Physics · Physics 2009-11-10 Artur Lozinski , Andreas Buchleitner , Karol Zyczkowski , Thomas Wellens

We summarise different aspects of the measurement problem in quantum mechanics. We argue that it is a real problem which requires a solution, and identify the properties a theory needs to solve the problem. We show that no current…

Quantum Physics · Physics 2022-11-15 Jonte R. Hance , Sabine Hossenfelder

A novel powerful mathematical method is presented, which allows us to find an analytical solution of a simplified version of the statistical multifragmentation model with the restriction that the largest fragment size cannot exceed the…

Nuclear Theory · Physics 2007-05-23 Kyrill A. Bugaev

We identify necessary and sufficient conditions for a quantum channel to be optimal for any convex optimization problem in which the optimization is taken over the set of all quantum channels of a fixed size. Optimality conditions for…

Quantum Physics · Physics 2021-05-05 Bryan Coutts , Mark Girard , John Watrous

We propose the necessary and sufficient condition for the presence of quantum entanglement in arbitrary symmetric pure states of two-level atomic systems. We introduce a parameter to quantify quantum entanglement in such systems. We express…

Quantum Physics · Physics 2011-11-22 Ram Narayan Deb

In this paper, we have considered the problem of general conclusive quantum state classification; the necessary and sufficient conditions for the existence of conclusive classification strategies have also been presented. Moreover, we have…

Quantum Physics · Physics 2007-05-23 Mei-Yu Wang , Feng-Li Yan

We consider the problem of a state determination for a two-level quantum system which can be in one of two nonorthogonal mixed states. It is proved that for the two independent identical systems the optimal combined measurement (which…

Quantum Physics · Physics 2007-05-23 A. E. Allahverdyan , D. B. Saakian

We address the problem of optimal estimation of the relative phase for two-dimensional quantum systems in mixed states. In particular, we derive the optimal measurement procedures for an arbitrary number of qubits prepared in the same mixed…

Quantum Physics · Physics 2007-05-23 Giacomo Mauro D'Ariano , Chiara Macchiavello , Paolo Perinotti

We would like to study the solution stability of a parametric control problem governed by semilinear elliptic equations with a mixed state-control constraint, where the cost function is nonconvex and the admissible set is unbounded. The…

Optimization and Control · Mathematics 2021-01-01 Nguyen Hai Son , Tuan Anh Dao

Probabilistic quantum state transformations can be characterized by the degree of state separation they provide. This, in turn, sets limits on the success rate of these transformations. We consider optimum state separation of two known pure…

Quantum Physics · Physics 2016-01-20 Emilio Bagan , Vadim Yerokhin , Andi Shehu , Edgar Feldman , Janos A. Bergou

We provide a constructive algorithm to find the best separable approximation to an arbitrary density matrix of a composite quantum system of finite dimensions. The method leads to a condition of separability and to a measure of…

Quantum Physics · Physics 2009-10-30 Maciej Lewenstein , Anna Sanpera

Determining the physical Hilbert space is often considered the most difficult but crucial part of completing the quantization of a constrained system. In such a situation it can be more economical to use effective constraint methods, which…

Mathematical Physics · Physics 2009-12-04 Martin Bojowald , Artur Tsobanjan

We study the geometric measure of quantum coherence recently proposed in [Phys. Rev. Lett. 115, 020403 (2015)]. Both lower and upper bounds of this measure are provided. These bounds are shown to be tight for a class of important coherent…

Quantum Physics · Physics 2017-03-14 Hai-Jun Zhang , Bin Chen , Ming Li , Shao-Ming Fei , Gui-Lu Long

If only limited control over a multiparticle quantum system is available, a viable method to characterize correlations is to perform random measurements and consider the moments of the resulting probability distribution. We present…

Quantum Physics · Physics 2021-04-23 Satoya Imai , Nikolai Wyderka , Andreas Ketterer , Otfried Gühne

Any given density matrix can be represented as an infinite number of ensembles of pure states. This leads to the natural question of how to uniquely select one out of the many, apparently equally suitable, possibilities. Following Jaynes'…

Quantum Physics · Physics 2025-04-23 Fabio Anza , James P. Crutchfield

We solve the quantum discord completely as an optimization of certain one variable function for arbitrary two qubit X state. Exact solutions of the quantum discord are obtained for several nontrivial regions of the five parametric space for…

Quantum Physics · Physics 2016-08-31 Naihuan Jing , Bing Yu

We consider the unambiguous discrimination of multipartite quantum states and provide an upper bound for the maximum success probability of optimal local discrimination. We also provide a necessary and sufficient condition to realize the…

Quantum Physics · Physics 2023-01-10 Donghoon Ha , Jeong San Kim