Rotational Friction and Diffusion of Quantum Rotors

Stickler, Benjamin A.; Schrinski, Björn; Hornberger, Klaus

doi:10.1103/physrevlett.121.040401

Cited by 57 publications

(43 citation statements)

References 55 publications

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“…the development of collisional-decoherence models that take into account both spatial and orientational decoherence of anisotropic molecules [181][182][183][184][185]; predictions derived from these models are in good agreement with experimental data [184].…”

Section: A Endogenous Heat Radiationmentioning

confidence: 64%

Quantum decoherence

2019

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Quantum decoherence plays a pivotal role in the dynamical description of the quantum-to-classical transition and is the main impediment to the realization of devices for quantum information processing. This paper gives an overview of the theory and experimental observation of the decoherence mechanism. We introduce the essential concepts and the mathematical formalism of decoherence, focusing on the picture of the decoherence process as a continuous monitoring of a quantum system by its environment. We review several classes of decoherence models and discuss the description of the decoherence dynamics in terms of master equations. We survey methods for avoiding and mitigating decoherence and give an overview of several experiments that have studied decoherence processes. We also comment on the role decoherence may play in interpretations of quantum mechanics and in addressing foundational questions.Keywords: quantum decoherence, quantum-to-classical transition, quantum measurement, quantum master equations, quantum information, quantum foundationsIn memory of H. Dieter Zeh 1 Of course, this must not be read as saying that S was already in |s 1 (i.e., "went through slit 1") prior to the measurement of E. Nor does it mean that the result of a subsequent path measurement on S is necessarily determined, by virtue of the measurement on E, prior to this S-measurement's actually being carried out. After all, as Peres [53] has cautioned us, unperformed measurements have no outcomes. So while the picture of E as "encoding which-path information" about S is certainly suggestive and helpful, it should be used with an understanding of its conceptual pitfalls. 6

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Section: A Endogenous Heat Radiationmentioning

confidence: 64%

Quantum decoherence

2019

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“…But it has recently been shown that the dominant noise in microwave cavities is sufficiently local for GKP codes to work effectively [3,4]. It remains to be seen whether the noise in realistic rigid rotors [133][134][135][136][137][138][139] has similarly benign properties.…”

Section: Discussionmentioning

confidence: 99%

“…To determine how well these codes protect against physical rigid-rotor noise models [133][134][135][136][137][138][139], one would expand the noise operators in terms of position and momentum shifts and estimate the probability of an uncorrectable error. A similar analysis for code states of harmonic oscillators rather than rotors [3, Sec.…”

Section: B Gates Recovery and Initializationmentioning

confidence: 99%

Encoding a qubit in a molecule

Albert

Covey

Preskill

2019

Rochester Conference on Coherence and Quantum Optics (CQO-11)

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We construct quantum error-correcting codes that embed a finite-dimensional code space in the infinite-dimensional Hilbert state space of rotational states of a rigid body. These codes, which protect against both drift in the body's orientation and small changes in its angular momentum, may be well suited for robust storage and coherent processing of quantum information using rotational states of a polyatomic molecule. Extensions of such codes to rigid bodies with a symmetry axis are compatible with rotational states of diatomic molecules, as well as nuclear states of molecules and atoms. We also describe codes associated with general nonabelian compact Lie groups and develop orthogonality relations for coset spaces, laying the groundwork for quantum information processing with exotic configuration spaces.

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“…This, somewhat cumbersome notation, is used in order to facilitate the presentation of the quantum Cauchy-Schwarz inequality, σ ϕL ≡ φL z +L zφ − 2 φ L z ≤ 2∆φ∆L z , which is satisfied by the choice of the initial values, p = 0.01, q = 0.005, r = 0, while A = ϕ (N ) We choose the values for γ • ∈ [0. 11,20] that are all larger than the chosen ω = 0.1. We find only weak dependence on the initial position and practically negligible contribution of k B T .…”

Section: The First Passage Timementioning

confidence: 99%

“…The requirement of rotational symmetry justifies, for some models, construction of the effective, rotationally symmetric interactions or external potentials for the rotator system [8]. The related quantum master equations are typically assumed or constructed to be Markovian [8][9][10][11], that is, of the Lindblad form [12,13].…”

Section: Introductionmentioning

confidence: 99%

Dynamical stability of the weakly nonharmonic propeller-shaped planar Brownian rotator

2020

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Dynamical stability is a prerequisite for control and functioning of desired nano-machines. We utilize the Caldeira-Leggett master equation to investigate dynamical stability of molecular cogwheels modeled as a rigid, propeller-shaped planar rotator. In order to match certain expected realistic physical situations, we consider a weakly nonharmonic external potential for the rotator.Two methods for investigating stability are used. First, we employ a quantum-mechanical counterpart of the so-called "first passage time" method. Second, we investigate time dependence of the standard deviation of the rotator for both the angle and angular momentum quantum observables.A perturbation-like procedure is introduced and implemented in order to provide the closed set of differential equations for the moments. Extensive analysis is performed for different combinations of the values of system parameters. The two methods are, in a sense, mutually complementary.Appropriate for the short time behavior, the first passage time exhibits a numerically-relevant dependence only on the damping factor as well as on the rotator size. On the other hand, the standard deviations for both the angle and angular momentum observables exhibit strong dependence on the parameter values for both short and long time intervals. Contrary to our expectations, the time decrease of the standard deviations is found for certain parameter regimes. In addition, for certain parameter regimes nonmonotonic dependence on the rotator size is observed for the standard deviations and for the damping of the oscillation amplitude. Hence non-fulfillment of the classical expectation that the size of the rotator can be reduced to the inertia of the rotator. In effect, the task of designing the desired protocols for the proper control of the molecular rotations becomes an optimization problem that

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Rotational Friction and Diffusion of Quantum Rotors

Cited by 57 publications

References 55 publications

Quantum decoherence

Quantum decoherence

Encoding a qubit in a molecule

Dynamical stability of the weakly nonharmonic propeller-shaped planar Brownian rotator

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