Monitoring the Decoherence of Mesoscopic Quantum Superpositions in a Cavity

Abstract

Abstract. Decoherence is an extremely fast and efficient environment-induced process transforming macroscopic quantum superpositions into statistical mixtures. It is an essential step in quantum measurement and a formidable obstacle for a practical use of quantum superpositions (quantum computing for instance). For large objects, decoherence is so fast that its dynamics is unobservable. Mesoscopic fields stored in a high-quality superconducting millimeter-wave cavity, a modern equivalent to Einstein's 'photon box', are ideal tools to reveal the dynamics of the decoherence process. Their interaction with a single circular Rydberg atom prepares them in a quantum superposition of fields, containing a few photons, with different classical phases. The evolution of this 'Schrödinger cat' state can be later probed with a 'quantum mouse', another atom, assessing its coherence. We describe here the experiments performed along these lines at ENS, and stress the deep links between decoherence and complementarity.

Some Trends in Quantum Thermodynamics

“…A description of the Cavity Quantum Electrodynamic (CQED) experimental system upon which the SEA-QT theoretical model is based is given in [73,[106][107][108][109][110][111]. A very brief description is provided here beginning with the experimental configuration depicted in In this manner, an entanglement between the states of the constituents is created.…”

“…Their efforts are attempts at building thermodynamics and irreversibility directly into the quantum dynamical level of description under the assumption that entropy and irreversibility have a microscopic foundation. Although there is no conclusive empirical evidence to prove these theories right or wrong, there is some empirical evidence, as seen, for example, in Sections 3.2 and 3.3 above, to at least suggest that one of these approaches, i.e., IQT, may indeed be a reasonable physical explanation for the phenomena of decoherence and decorrelation recently experimentally reported at a microscopic level [106][107][108][109][110][111][112][113]116]. Furthermore, although the validity of the ansatz of a fundamental nonlinearity at the quantum level of description has often been criticized as incompatible with the so-called "no-signaling condition", recent work by Ferreo, Salgado, and Sánchez-Gómez [132] suggests that nonlinear quantum evolution is in principle perfectly compatible with the impossibility of supraluminal communication, thus, reopening the discussion of fundamental non-linearity from this standpoint as well.…”

Yes, More Decoherence: A Reply to Critics

“…(Haroche, 2012, pp. 90-91) Similar experiments are reported in Bernu et al (2008), Bertet et al (2002), Davidovich et al (1996), Deléglise et al (2008), Raimond et al (2001) and Raimond and Haroche (2005). Let us consider more carefully a study of this type titled "Scheme to probe the decoherence of a macroscopic object" (Bose et al, 1999).…”

Exploring Philosophical Implications of Quantum Decoherence

“… Such experiments notably include the creation of Schrödinger ‘kittens’ (a gentle introduction to this sort of experimental work is given in the work of Raimond and Haroche ) and the experiments in molecular interferometry referenced above in Section 2.4.…”