Fragility of superposition states evaluated by the Loschmidt Echo

Abstract

We consider the degradation of the dynamics of a Gaussian wave packet in a harmonic oscillator under the presence of an environment. This last is given by a single non-degenerate two level system. We analyze how the binary degree of freedom perturbs the free evolution of the wave packet producing decoherence, which is quantified by the Loschmidt Echo. This magnitude measures the reversibility of a perturbed quantum evolution. In particular, we use it here to study the relative "fragility" of coherent superpositions (cat states) with respect to incoherent ones. This fragility or sensitivity turns to increase exponentially with the energy separation of the two components of the superposition.

12 pages, 6 figures

References in corpus (8)

• Many-Body Physics with Ultracold Gases
• Dynamics of Loschmidt echoes and fidelity decay
• Loschmidt Echo
• Decoherence, Entanglement and Irreversibility in Quantum Dynamical Systems with Few Degrees of Freedom
• Crucial role of decoherence for electronic transport in molecular wires: Polyaniline as a case study
• Quantum parallelism as a tool for ensemble spin dynamics calculations
• The Loschmidt Echo as a robust decoherence quantifier for many-body systems
• Quantum Reversibility and Echoes in Interacting Systems

Cited by in corpus (6)

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• Conditional past-future correlation induced by non-Markovian dephasing reservoirs
• Loschmidt echo in many-spin systems: contrasting time-scales of local and global measurements
• Proliferation of effective interactions: decoherence-induced equilibration in a closed many-body system
• Loschmidt echo in many-spin systems: a quest for intrinsic decoherence and emergent irreversibility
• Harmonic oscillator kicked by spin measurements: a Floquet-like system without classical analogous