Arrested relaxation in an isolated molecular ultracold plasma

Edward Grant (UBC)
Event Date and Time: 
Wed, 2016-04-27 11:00 - 12:00
TRIUMF Auditorium

The eigenstate thermalization hypothesis (ETH) holds that the energy eigenstates underlying an evolving superposition mimic thermal states of the system [1, 2]. Thus, in this picture - despite the deterministic nature of the Schroedinger equation and the absence of outside perturbations - an arbitrarily prepared isolated quantum system relaxes to a thermal equilibrium that is somehow hardwired in its eigenstates. Indeed, ergodic dynamics have been found in a quantum system as small as three transmon qubits [3].

However, theory predicts the existence of certain interacting many-body systems that lack intrinsic decoherence and preserve topological order in highly excited states. These systems exhibit local observables that retain a memory of initial conditions for arbitrarily long times. Such behaviour has important practical and fundamental implications. For this reason, experimental realizations of isolated quantum systems that fail to thermalize have attracted a great deal of interest [4, 5].

Here we describe particular conditions under which an ultracold plasma evolves from a molecular Rydberg gas of nitric oxide, adiabatically sequesters energy in a reservoir of mass transport, and relaxes to form a spatially correlated strongly coupled plasma. Short-time electron spectroscopy provides evidence for complete ionization. The long lifetime of the system, particularly its stability with respect to recombination and neutral dissociation, suggest a robust process of self organization to reach a state of arrested relaxation, far from thermal equilibrium.

[1]  Rigol M, Dunjko V, Olshanii M: Thermalization and its mechanism for generic isolated quantum systems. Nature 2008, 452:854-858.
[2]  Eisert J, Friesdorf M, Gogolin C: Quantum many-body systems out of equilibrium. Nature Physics 2015, 11(2):124-130.
[3]  Neill C, et al: Ergodic dynamics and thermalization in an isolated quantum system. arXiv: 2016, 1601.00600v2.
[4]  Kondov SS, McGehee WR, Xu W, DeMarco B: Disorder-Induced Localization in a Strongly Correlated Atomic Hubbard Gas. Phys Rev Lett  2015, 114:083002.
[5]  Schreiber M, Hodgman SS, Bordia P, Luschen HP, Fischer MH, Vosk R, Altman E, Schneider U, Bloch I: Observation of many-body localization of interacting fermions in a quasi-random optical lattice. Science 2015, 349:842-845.

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