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The Kochen-Specker (KS) theorem is a central result in quantum theory and has applications in quantum information. Its proof requires several yes-no tests that can be grouped in contexts or subsets of jointly measurable tests. Arguably, the…

Quantum Physics · Physics 2014-04-23 Petr Lisonek , Piotr Badziag , Jose R. Portillo , Adan Cabello

We propose a numerical algorithm for finding optimal measurements for quantum-state discrimination. The theory of the semidefinite programming provides a simple check of the optimality of the numerically obtained results.

Quantum Physics · Physics 2016-09-08 M. Jezek , J. Rehacek , J. Fiurasek

The elements of a deterministic quantum theory are developed, which reformulates and extends standard quantum theory. The proposed theory is `realistic' in the sense that in it, a general M-level quantum state is represented by a single…

Quantum Physics · Physics 2007-05-23 T. N. Palmer

Quantum theory is traditionally formulated using complex numbers. This imaginarity of quantum theory has been quantified as a resource with applications in discrimination tasks, pseudorandomness generation, and quantum metrology. Here we…

Quantum Physics · Physics 2024-11-15 Carlos Fernandes , Rafael Wagner , Leonardo Novo , Ernesto F. Galvão

Does there exist a limit for the applicability of quantum theory for objects of large mass or size, or objects whose states are of large complexity or dimension of the Hilbert space? The possible answers range from practical limitations due…

Quantum Physics · Physics 2010-09-15 Johannes Kofler , Caslav Brukner

We study an optimized measurement that discriminates two mixed quantum states with maximum confidence for each conclusive result, thereby keeping the overall probability of inconclusive results as small as possible. When the rank of the…

Quantum Physics · Physics 2009-11-13 Ulrike Herzog

In classical statistical decision theory, comparison of experiments plays very important role. Especially, so-called randomization criteria is most important. In this paper, we establish two kinds of quantum analogue these concepts, and…

Quantum Physics · Physics 2015-05-20 Keiji Matsumoto

Quantum simulations are becoming an essential tool for studying complex phenomena, e.g. quantum topology, quantum information transfer, and relativistic wave equations, beyond the limitations of analytical computations and experimental…

It is often stated that complex numbers are essential in quantum theory. In this article, the need for complex numbers in quantum theory is motivated using the results of tandem Stern-Gerlach experiments

Quantum Physics · Physics 2012-07-16 S. Sivakumar

We show that, regardless of the dimension of the Hilbert space, there exists no set of rays revealing state-independent contextuality with less than 13 rays. This implies that the set proposed by Yu and Oh in dimension three [Phys. Rev.…

Quantum Physics · Physics 2016-09-12 Adán Cabello , Matthias Kleinmann , José R. Portillo

Recently Quantum Computation has generated a lot of interest due to the discovery of a quantum algorithm which can factor large numbers in polynomial time. The usefulness of a quantum com puter is limited by the effect of errors. Simulation…

Quantum Physics · Physics 2007-05-23 Kevin M. Obenland , Alvin M. Despain

Physicists describe nature using mathematics as the natural language, and for quantum mechanics, it prefers to use complex numbers. However, whether complex numbers are really necessary for the theory has been debated ever since its birth.…

Computer simulation of observable phenomena is an indispensable tool for engineering new technology, understanding the natural world, and studying human society. Yet the most interesting systems are often complex, such that simulating their…

Quantum Physics · Physics 2017-08-23 Matthew S. Palsson , Mile Gu , Joseph Ho , Howard M. Wiseman , G. J. Pryde

The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics, the objectivity of observations is not so clear, most dramatically…

The uncertainty relation is a distinguishing feature of quantum theory, characterizing the incompatibility of noncommuting observables in the preparation of quantum states. Recently, many uncertainty relations were proposed with improved…

Quantum Physics · Physics 2017-12-25 Zhi-Xin Chen , Jun-Li Li , Qiu-Cheng Song , Hui Wang , S. M. Zangi , Cong-Feng Qiao

We present a method to test quantum behavior of quantum information processing devices, such as quantum memories, teleportation devices, channels and quantum key distribution protocols. The test of quantum behavior can be phrased as the…

Quantum Physics · Physics 2008-03-07 Hauke Häseler , Tobias Moroder , Norbert Lütkenhaus

Quantum physics constrains the accuracy of joint measurements of incompatible observables. Here we test tight measurement-uncertainty relations using single photons. We implement two independent, idealized uncertainty-estimation methods,…

Three recent arguments seek to show that the universal applicability of unitary quantum theory is inconsistent with the assumption that a well-conducted measurement always has a definite physical outcome. In this paper I restate and analyze…

Quantum Physics · Physics 2018-10-17 Richard A. Healey

Self-testing usually refers to the task of taking a given set of observed correlations that are assumed to arise via a process that is accurately described by quantum theory, and trying to infer the quantum state and measurements. In other…

Quantum Physics · Physics 2024-01-17 Mirjam Weilenmann , Roger Colbeck

We will focus on the Quantum theory and starting from simple philosophical conjectures, we infer possible different physical realities. Also we argue of possible wavefunction emerging under specific conditions of the physical reality.…

General Physics · Physics 2007-05-23 Helen Lynn , Michele Caponigro