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We demonstrate by an explicit model calculation that the decay of entanglement of two two-state systems (two qubits) is governed by the product of the factors that measure the degree of decoherence of each of the qubits, subject to…

Quantum Physics · Physics 2010-10-12 D. Tolkunov , V. Privman , P. K. Aravind

Attenuating a quantum state using a beam splitter will introduce noise and decoherence. Here we show that heralding techniques can be used to attenuate Schr\"odinger cat states and squeezed vacuum states without any noise or decoherence…

Quantum Physics · Physics 2022-01-11 S. U. Shringarpure , C. M. Nunn , T. B. Pittman , J. D. Franson

Quantum technologies have shown immeasurable potential to effectively solve several information processing tasks such as prime number factorization, unstructured database search or complex macromolecule simulation. As a result of such…

Quantum Physics · Physics 2022-03-08 Josu Etxezarreta Martinez

Quantum information is typically encoded in the state of a qubit that is decoupled from the environment. In contrast, waveguide quantum electrodynamics studies qubits coupled to a mode continuum, exposing them to a loss channel and causing…

It is known that a quantum system with finite degrees of freedom can simulate a composite of a system and an environment if the state of the hypothetical environment is randomized by external manipulation. We show theoretically that any…

Quantum Fourier transform is of primary importance in many quantum algorithms. In order to eliminate the destructive effects of decoherence induced by couplings between the quantum system and its environment, we propose a robust scheme for…

Quantum Physics · Physics 2007-05-23 Jian-wu Wu , Chun-wen Li , Re-bing Wu

Quantum entanglement and decoherence are the two counterforces of many quantum technologies and protocols. For example, while quantum teleportation is fueled by a pair of maximally entangled resource qubits, it is vulnerable to decoherence.…

Spontaneous emission and the inelastic scattering of photons are two natural processes usually associated with decoherence and the reduction in the capacity to process quantum information. Here we show that when suitably detected, these…

Quantum Physics · Physics 2012-04-27 Marcelo F. Santos , Marcelo Terra Cunha , Rafael Chaves , Andre R. R. Carvalho

Due to omnipresent environmental interferences, quantum coherences inevitably undergo irreversible transformations over certain time-scales, thus leading to the loss of encoded information. This process, known as decoherence, has been a…

Quantum Physics · Physics 2014-06-19 Swathi S. Hegde , T. S. Mahesh

Quantum superpositions can be used for parallel information processing, but only if protected against decoherence. A two-particle four-state system may have two-dimensional subspaces that are partially or completely decoherence-free, e.g.,…

Quantum Physics · Physics 2007-05-23 Jeffrey Satinover

When the environmental disturbace to a quantum system has a wavelength much larger than the system size, all qubits localized within a small area are under action of the same error operators. Noiseless subsystem and decoherence free…

Quantum Physics · Physics 2013-05-29 Chi-Kwong Li , Mikio Nakahara , Yiu-Tung Poon , Nung-Sing Sze , Hiroyuki Tomita

We address the problem of completely characterizing multi-particle states including loss of information to unobserved degrees of freedom. In systems where non-classical interference plays a role, such as linear-optics quantum gates, such…

Quantum Physics · Physics 2009-11-13 R. B. A. Adamson , L. K. Shalm , M. W. Mitchell , A. M. Steinberg

The states of the physical algebra, namely the algebra generated by the operators involved in encoding and processing qubits, are considered instead of those of the whole system-algebra. If the physical algebra commutes with the interaction…

Quantum Physics · Physics 2009-10-31 Sergio De Filippo

We study and experimentally implement a double-slit quantum eraser in the presence of a controlled decoherence mechanism. A two-photon state, produced in a spontaneous parametric down conversion process, is prepared in a maximally entangled…

Quantum Physics · Physics 2015-05-14 F. A. Torres-Ruiz , G. Lima , A. Delgado , S. Pádua , C. Saavedra

Low-frequency noise presents a serious source of decoherence in solid-state qubits. When combined with a continuous weak measurement of the eigenstates, the low-frequency noise induces a second-order relaxation between the qubit states.…

Quantum Physics · Physics 2011-07-26 L. Tian

The decoherence induced on a single qubit by its interaction with the environment is studied. The environment is modelled as a scalar two-level boson system that can go through either first order or continuous excited state quantum phase…

Quantum Physics · Physics 2015-05-14 P. Perez-Fernandez , A. Relano , J. M. Arias , J. Dukelsky , J. E. Garcia-Ramos

Quantum error correction is a set of methods to protect quantum information--that is, quantum states--from unwanted environmental interactions (decoherence) and other forms of noise. The information is stored in a quantum error-correcting…

Quantum Physics · Physics 2024-10-01 Todd A. Brun

Decoherence in quantum computer memory due to the inevitable coupling to the external environment is examined. We take the assumption that all quantum bits (qubits) interact with the same environment rather than the assumption of separate…

Quantum Physics · Physics 2009-10-30 Lu-Ming Duan , Guang-Can Guo

The interaction between solid-state qubits and their environmental degrees of freedom produces non-unitary effects like decoherence and dissipation. Uncontrolled decoherence is one of the main obstacles that must be overcome in quantum…

Quantum Physics · Physics 2014-11-24 Paula I. Villar , Fernando C. Lombardo

The cause of decoherence in a quantum system can be traced back to the interaction with the environment. As it has been pointed out first by Dicke, in a system of N two-level atoms where each of the atoms is individually dipole coupled to…

Quantum Physics · Physics 2009-11-07 Peter Foldi , Mihaly G. Benedict , Attila Czirjak