Decoherence factor as a convolution: an interplay between a Gaussian and an exponential coherence loss
Abstract We identify and investigate the origin and nature of the transition between Gaussian and exponential forms of decoherence: The decoherence factor (that controls the time dependence of the off-diagonal terms of the density matrix expressed in the pointer basis representation) is the convolution of the Fourier transforms of the spectral density and of the overlap (between the eigenstates the environment with and without couplings to the system). Spectral density alone tends to lead to the (approximately) Gaussian decay of coherence while the overlap alone results in a (largely) exponential decay. We show that these two contributions combine as a convolution, their relative importance controlled by the strength of the system- environment coupling. The resultant decoherence factor in the strong and weak coupling limits leads to predominantly Gaussian or exponential decay, respectively, as is demonstrated with two paradigmatic examples of decoherence—a spin-bath model and the quantum Brownian motion.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
- Grant/Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1899182
- Alternate ID(s):
- OSTI ID: 1896927; OSTI ID: 1906027
- Report Number(s):
- LA-UR-21-28440
- Journal Information:
- New Journal of Physics, Journal Name: New Journal of Physics Vol. 24 Journal Issue: 11; ISSN 1367-2630
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
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