Nonexponential Decoherence and Subdiffusion in Atom-Optics Kicked Rotor

Abstract

Quantum systems lose coherence upon interaction with the environment and tend towards classical states. Quantum coherence is known to exponentially decay in time so that macroscopic quantum superpositions are generally unsustainable. In this work, slower than exponential decay of coherences is experimentally realized in an atom-optics kicked rotor system subjected to nonstationary Lévy noise in the applied kick sequence. The slower coherence decay manifests in the form of quantum subdiffusion that can be controlled through the Lévy exponent. The experimental results are in good agreement with the analytical estimates and numerical simulations for the mean energy growth and momentum profiles of an atom-optics kicked rotor.

Simulating Floquet topological phases in static systems

“…All topological properties are lost in the long time limit as the system evolves towards a uniform, featureless steady state. The problem of decoherence due to driving noise has been recognized both theoretically and experimentally, starting from early measurements of the quantum kicked rotor in the 90s [89,90], and an active research field has emerged from studying and attempting to mitigate this effect [26,27,[91][92][93][94][95][96][97][98][99][100][101][102][103][104]. In our work, we have found a way of eliminating this effect completely: driving noise cannot lead to decoherence if unitary topological phases are realized without any driving.…”

Starobinsky-like inflation and neutrino masses in a no-scale SO(10) model

“…A supersymmetric version of this "minimal" theory was discussed in Ref. [52]. In this version of SO(10), the 126 and 126 are replaced by a pair of 16 and 16, and there is one singlet per generation, one of which is identified as the inflaton.…”

“…The SM singlet components of Φ,Φ, and Σ can acquire non-vanishing vevs through the couplings included in the fifth through eighth terms. After these fields develop vevs, the αHΦΦ andᾱHΦΦ terms induce mixing among the SU(2) L doublet components inside H, Φ, andΦ, and by appropriately choosing these couplings we can make two linear combinations of these fields, denoted by H u and H d , much lighter than the GUT and intermediate scales [52], thereby realizing the desirable doublet-triplet splitting. The vevs of these fields then break the SM gauge group at the electroweak symmetry breaking scale as in the MSSM.…”

“…(9) contains several terms that are additional to those in the minimal model in Ref. [52], notably those with the couplings λ, λ SH , M, α ′ , c, b ′ , and γ. In Ref.…”

“…In Ref. [52], there is an extra Z 2 symmetry (besides the SO(10) gauge symmetry) that forbids these couplings, which is obtained by modifying the definition of R-parity as R = (−1) 3(B−L)+2s+χ , where χ is a new quantum number: 1 for S, Φ, andΦ, and 0 for the other fields. However, for Starobinsky-type inflation, we must have a term that is cubic in the singlet inflaton, thus we do not introduce such an extra Z 2 symmetry.…”