Quantum Chaos and Intrinsic Decoherence in Many Spin Systems

KEN XUAN WEI; HORACIO M. PASTAWSKI; CLAUDIA M. SÁNCHEZ; PAOLA CAPPELLARO; ANA K. CHATTAH

Easton

Conferencia; Gordon Research Conference, Quantum Science; 2018

Our Central Hypothesis of Irreversibility states that many-body dynamics at high temperatures is chaotic andhence should present an instability towards time-reversal in a Loschmidt Echo experiment. The irreversibilitytime-scale T3 should be the tied to the many-body mixing time T2 fixed by the second moment of the dipolarHamiltonian. To test this, we implement a pulse sequence which allows the system to evolve with scaled dipolarHamiltonian in polycrystalline Adamantane. The pulse sequence is a mixture of the Proportionally RefocusedLoschmidt echo (PRL echo) and the standard Magic echo (ME). A Forward and/or a backward dynamics arecharacterized by a zero order Hamiltonian representing the homonuclear dipolar interaction H0 modulated by afactor k. The experiments were carried out with different scaling factors to analyze the evolution of the total magnetizationand the Loschmidt echo. In all cases, a strong dependence between the evolution rate and the scalingfactor is observed.