Chinese Physics Letters

Effect of Noise on Berry‘s Phase for Quantum Computing

Jinghui, GEMo-Lin

Published Jan 1, 2003• 0 citations

Abstract

Based on a new type of two-level-system reservoir, we investigate the impact of dissipation on Berry''s phase of a spin trapped in a periodical external field. It is found that the existence of environmental noise could lead to a decaying term in the matrix of Berry's phase as the sign of a decoherence process, which is in agreement with the result of Nazir et al. (Phys. Rev. A 65 (2002) 042303). Particularly, in comparison with a specialized case of the traditional Leggett dissipation model, we only shows the dependence of time but not temperature in decaying tem. A concrete case is exhibited by using the one-dimensional Ohmic function.

Related papers

Effect of Noise on Berry's Phase for Quantum Computing

Jing Hui, Mo‐Lin Ge

Based on a new type of two-level-system reservoir, we investigate the impact of dissipation on Berry's phase of a spin trapped in a periodical external field. It is found that the existence of environmental noise could lead to a decaying term in the matrix of Berry's phase as the sign of a decoherence process, which is in agreement with the result of Nazir et al. (Phys. Rev. A 65 (2002) 042303). Particularly, in comparison with a specialized case of the traditional Leggett dissipation model, we only shows the dependence of time but not temperature in decaying term. A concrete case is exhibited by using the one-dimensional Ohmic function.

Chinese Physics LettersMay 16, 20030 citations

Effect of decoherence on the Berry phase of a spin-half in a rotating magnetic field

Xin Li, Yu Shi

We investigate the decoherence effect of a bosonic bath on the Berry phase of a spin- in a time-dependent magnetic field, without making the Markovian approximation. A two-cycle process resulting in a pure Berry phase is considered. The low-frequency quantum noise significantly affects the Berry phase. In the adiabatic limit, the high-frequency quantum noise only has a small effect. The result is also valid in some more general situations.

arXiv:1308.2821Europhysics Letters (EPL)Jul 1, 20131 citation

Geometric phase of a two-state system in noisy environment

Kazuo Fujikawa, Ming-Guang Hu

The geometric (Berry) phase of a two-level system in a dissipative environment is analyzed by using the second-quantized formulation, which provides a unified and gauge-invariant treatment of adiabatic and nonadiabatic phases and is thus applicable to a quantitative analysis of transitional regions away from ideal adiabaticity. In view of the recent experimental observation of the Berry phase in a superconducting qubit, we illustrate our formulation for a concrete adiabatic case in the Ohmic dissipation. The correction to the total phase together with the geometry-dependent dephasing time is given in a transparent way. The behavior of the geometric phase away from ideal adiabaticity is also analyzed in some detail.

May 6, 20080 citations

Exploring the effect of noise on the Berry phase

S. Berger, Marek Pechal, A. A. Abdumalikov +5 more

We experimentally investigate the effects of noise on the adiabatic and cyclic geometric phase, also termed the Berry phase. By introducing artificial fluctuations in the path of the control field, we measure the geometric contribution to dephasing of an effective two-level system for a variety of noise powers and different paths. Our results, measured using a microwave-driven superconducting qubit, clearly show that only fluctuations which distort the path lead to geometric dephasing. In a direct comparison with the dynamic phase, which is path independent, we observe that the Berry phase is less affected by noise-induced dephasing. This observation directly points towards the potential of geometric phases for quantum gates or metrological applications.

arXiv:1302.3305Physical Review AJun 26, 2013101 citations

Environmental suppression of non-adiabatic phases: easier observation of Berry phases

Robert S. Whitney

We consider a two-level system coupled to a highly non-Markovian environment when the coupling axis rotates with time. The environment may be quantum (for example a bosonic bath or a spin bath) or classical (such as classical noise). We show that an Anderson orthogonality catastrophe suppresses transitions, so that the system's instantaneous eigenstates (parallel and anti-parallel to the coupling axis) can adiabatically follow the rotation. These states thereby acquire Berry phases; geometric phases given by the area enclosed by the coupling axis. Unlike in earlier proposals for environment-induced Berry phases, here there is little decoherence, so one does not need a decoherence-free subspace. Indeed we show that this Berry phase should be much easier to observe than a conventional one, because it is not masked by either the dynamic phase or the leading non-adiabatic phase. The effects that we discuss should be observable in any qubit device where one can drive three parameters in the Hamiltonian with strong man-made noise.

Jun 30, 20080 citations

Berry phase with environment: classical versus quantum

Robert S. Whitney, Yuriy Makhlin, Alexander Shnirman +1 more

We discuss the concept of the Berry phase in a dissipative system. We show that one can identify a Berry phase in a weakly-dissipative system and find the respective correction to this quantity, induced by the environment. This correction is expressed in terms of the symmetrized noise power and is therefore insensitive to the nature of the noise representing the environment, namely whether it is classical or quantum mechanical. It is only the spectrum of the noise which counts. We analyze a model of a spin-half (qubit) anisotropically coupled to its environment and explicitly show the coincidence between the effect of a quantum environment and a classical one.

arXiv:cond-mat/0401376Jan 21, 20040 citations