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Quantum error avoiding codes are constructed by exploiting a geometric interpretation of the algebra of measurements of an open quantum system. The notion of a generalized Dirac operator is introduced and used to naturally construct…

Quantum Physics · Physics 2007-05-23 David D. Song , Richard J. Szabo

It is commonly stated that decoherence in open quantum systems is due to growing entanglement with an environment. In practice, however, surprisingly often decoherence may equally well be described by random unitary dynamics without…

Quantum Physics · Physics 2009-10-29 Julius Helm , Walter T. Strunz

The information in quantum computers is often stored in identical two-level systems (spins or pseudo-spins) that are separated by a distance shorter than the characteristic wavelength of a reservoir which is responsible for decoherence. In…

Quantum Physics · Physics 2016-09-08 Shoko Utsunomiya , Cyrus P. Master , Yoshihisa Yamamoto

Geometric phases depend only on the evolution path determined by the closed circuit in the projective Hilbert space but not on evolution details of the quantum system, leading to geometric quantum computation possessing some intrinsic…

Quantum Physics · Physics 2025-09-05 X. Y. Sun , P. Z. Zhao

Given a real number $q$ such that $0<q<1$, the natural setting for the mathematics of a $q$-oscillator is an infinite-dimensional, separable Hilbert space that is said to provide an interpolation between the Bargmann-Segal space of…

Operator Algebras · Mathematics 2023-02-15 Rafael Reno S. Cantuba

We present a general unified approach for finding the coherent states of polynomially deformed algebras such as the quadratic and Higgs algebras, which are relevant for various multiphoton processes in quantum optics. We give a general…

Quantum Physics · Physics 2015-06-26 V. SunilKumar , B. A. Bambah , R. Jagannathan , P. K. Panigrahi , V. Srinivasan

Coherence in an open quantum system is degraded through its interaction with a bath. This decoherence can be avoided by restricting the dynamics of the system to special decoherence-free subspaces. These subspaces are usually constructed…

Quantum Physics · Physics 2016-09-08 Daniel A. Lidar , Dave Bacon , Julia Kempe , K. B. Whaley

In Quantum Physics, a measurement is represented by a projection on some closed subspace of a Hilbert space. We study algebras of operators that abstract from the algebra of projections on closed subspaces of a Hilbert space. The properties…

Quantum Physics · Physics 2007-05-23 Daniel Lehmann , Kurt Engesser , Dov M. Gabbay

We provide a unified approach for finding the coherent states of various deformed algebras, including quadratic, Higgs and q-deformed algebras, which are relevant for many physical problems. For the non-compact cases, coherent states, which…

Quantum Physics · Physics 2007-05-23 V. Sunilkumar , B. A. Bambah , P. K. Panigrahi , V. Srinivasan

The quantum theory of decoherence plays an important role in a pragmatist interpretation of quantum theory. It governs the descriptive content of claims about values of physical magnitudes and offers advice on when to use quantum…

Quantum Physics · Physics 2012-07-30 Richard Healey

Universal quantum computation using optical coherent states is studied. A teleportation scheme for a coherent-state qubit is developed and applied to gate operations. This scheme is shown to be robust to detection inefficiency.

Quantum Physics · Physics 2009-11-07 H. Jeong , M. S. Kim

An algorithm for quantum computing Hamiltonian cycles of simple, cubic, bipartite graphs is discussed. It is shown that it is possible to evolve a quantum computer into an entanglement of states which map onto the set of all possible paths…

Quantum Physics · Physics 2007-05-23 T. Rudolph

The quantum nature of a microscopic system can only be revealed when it is sufficiently decoupled from surroundings. Interactions with the environment induce relaxation and decoherence that turn the quantum state into a classical mixture.…

Mesoscale and Nanoscale Physics · Physics 2017-09-12 Alexey M. Shakirov , Alexey N. Rubtsov , Alexander I. Lichtenstein , Pedro Ribeiro

Most quantum computer realizations require the ability to apply local fields and tune the couplings between qubits, in order to realize single bit and two bit gates which are necessary for universal quantum computation. We present a scheme…

Quantum Physics · Physics 2009-11-07 Xingxiang Zhou , Zheng-Wei Zhou , Guang-Can Guo , Marc J. Feldman

An algebraic formalism for quantum decoherence in systems with continuous evolution spectrum is introduced. A certain subalgebra, dense in the characteristic algebra of the system, is defined in such a way that Riemann-Lebesgue theorem can…

Mathematical Physics · Physics 2019-08-17 M. A. Castagnino , A. R. Ordoniez

Any quantum resource theory is based on free states and free operations, i.e., states and operations which can be created and performed at no cost. In the resource theory of coherence free states are diagonal in some fixed basis, and free…

Quantum Physics · Physics 2017-01-06 Julio I. de Vicente , Alexander Streltsov

When two or more subsystems of a quantum system interact with each other they can become entangled. In this case the individual subsystems can no longer be described as pure quantum states. For systems with only 2 subsystems this…

Quantum Physics · Physics 2007-05-23 Rachel Parker , Chris Doran

It is proposed the scheme of quantum mechanics, in which a Hilbert space and the linear operators are not primary elements of the theory. Instead of it certain variant of the algebraic approach is considered. The elements of noncommutative…

Quantum Physics · Physics 2007-05-23 D. A. Slavnov

We show that, for a Quantum Markov Semigroup (QMS) with a faithful normal invariant state, the atomicity of the decoherence-free subalgebra and environmental decoherence are equivalent. Moreover, we characterize the set of reversible states…

Quantum Physics · Physics 2017-12-05 F. Fagnola , E. Sasso , V. Umanita'

The dynamical evolution of a quantum register of arbitrary length coupled to an environment of arbitrary coherence length is predicted within a relevant model of decoherence. The results are reported for quantum bits (qubits) coupling…

Quantum Physics · Physics 2009-11-07 John H. Reina , Luis Quiroga , Neil F. Johnson