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Structured decompositions of a desired unitary operator are employed to derive control schemes that achieve certain control objectives for finite-level quantum systems using only sequences of simple control pulses such as square waves with…

Quantum Physics · Physics 2007-05-23 S. G. Schirmer , A. D. Greentree , V. Ramakrishna , H. Rabitz

Traditional quantum state tomography requires a number of measurements that grows exponentially with the number of qubits n. But using ideas from computational learning theory, we show that "for most practical purposes" one can learn a…

Quantum Physics · Physics 2009-11-13 Scott Aaronson

For a given pure state of a composite quantum system we analyze the product of its projections onto a set of locally orthogonal separable pure states. We derive a bound for this product analogous to the entropic uncertainty relations. For…

Quantum Physics · Physics 2015-05-28 Łukasz Rudnicki , Paweł Horodecki , Karol Życzkowski

Simple constructions and protocols are demonstrated to allow the implementation of universal quantum computation on an arbitrarily large quantum system by controlling a fixed number of spins, vastly reducing the engineering requirements in…

Quantum Physics · Physics 2009-04-23 Alastair Kay

The usual formulation of quantum theory is rather abstract. In recent work I have shown that we can, nevertheless, obtain quantum theory from five reasonable axioms. Four of these axioms are obviously consistent with both classical…

Quantum Physics · Physics 2007-05-23 Lucien Hardy

We consider situations in which i) Alice wishes to send quantum information to Bob via a noisy quantum channel, ii) Alice has a classical description of the states she wishes to send and iii) Alice can make use of a finite amount of…

Quantum Physics · Physics 2009-11-07 Jonathan Barrett

The influence of additional information on the decision making of agents, who are interacting members of a society, is analyzed within the mathematical framework based on the use of quantum probabilities. The introduction of social…

Physics and Society · Physics 2015-10-14 V. I. Yukalov , D. Sornette

Duality transformations within the quantum mechanics of a finite number of degrees of freedom can be regarded as the dependence of the notion of a quantum, i.e., an elementary excitation of the vacuum, on the observer on classical phase…

High Energy Physics - Theory · Physics 2015-06-26 J. M. Isidro

Quantum theory can be derived from purely informational principles. Five elementary axioms-causality, perfect distinguishability, ideal compression, local distinguishability, and pure conditioning-define a broad class of theories of…

Quantum Physics · Physics 2015-03-17 G. Chiribella , G. M. D'Ariano , P. Perinotti

In this paper we present two flavors of a quantum extension to the lambda calculus. The first one, $\lambda_\rho$, follows the approach of classical control/quantum data, where the quantum data is represented by density matrices. We provide…

Logic in Computer Science · Computer Science 2017-11-21 Alejandro Díaz-Caro

Observational entropy is interpreted as the uncertainty an observer making measurements associates with a system. So far, properties that make such an interpretation possible rely on the assumption of ideal projective measurements. We show…

Quantum Physics · Physics 2023-12-11 Dominik Šafránek , Juzar Thingna

The interpretation of quantum mechanics has been discussed since this theme first was brought up by Einstein and Bohr. This article describes a proposal for a new foundation of quantum theory, partly drawing upon ideas from statistical…

Quantum Physics · Physics 2019-05-17 Inge S. Helland

One notion of non-locality in quantum theory is the fact that information may be encoded in a composite system in such a way that it is not accessible through local measurements, even with the assistance of classical communication. Thus,…

Quantum Physics · Physics 2022-10-05 Sarah Croke

We reconstruct the explicit formalism of qubit quantum theory from elementary rules on an observer's information acquisition. Our approach is purely operational: we consider an observer O interrogating a system S with binary questions and…

Quantum Physics · Physics 2018-03-14 Philipp A Hoehn , Christopher Wever

Algorithmic approach is based on the assumption that any quantum evolution of many particle system can be simulated on a classical computer with the polynomial time and memory cost. Algorithms play the central role here but not the…

Quantum Physics · Physics 2007-05-23 Yuri Ozhigov

The possibility of a quantum system to exhibit properties that are akin to both the classically held notions of being a particle and a wave, is one of the most intriguing aspects of the quantum description of nature. These aspects have been…

Quantum Physics · Physics 2025-01-23 Sreetama Das , Indranil Chakrabarty , Arun Kumar Pati , Aditi Sen De , Ujjwal Sen

A formula for the capacity of a quantum channel for transmitting private classical information is derived. This is shown to be equal to the capacity of the channel for generating a secret key, and neither capacity is enhanced by forward…

Quantum Physics · Physics 2007-05-23 I. Devetak

We derive two complementarity relations that constrain the individual and bipartite properties that may simultaneously exist in a multi-qubit system. The first expression, valid for an arbitrary pure state of n qubits, demonstrates that the…

Quantum Physics · Physics 2009-11-10 Tracey E. Tessier

Our knowledge of quantum mechanics can satisfactorily describe simple, microscopic systems, but is yet to explain the macroscopic everyday phenomena we observe. Here we aim to shed some light on the quantum-to-classical transition as seen…

Quantum Physics · Physics 2020-08-14 Isadora Veeren , Fernando de Melo

Difficulties and discomfort with the interpretation of quantum mechanics are due to differences in language between it and classical physics. Analogies to The Special Theory of Relativity, which also required changes in the basic worldview…

Quantum Physics · Physics 2015-06-26 A. R. P. Rau