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Title
Loschmidt echo and dynamical fidelity in periodically driven quantum system
Lecturer
Ms. Shraddha Sharma (Indian Institute of Technology Kanpur, India)
Date and time
May,16,2014, 10:45-12:15
Place
H284B, Main Building, O-Okayama Campus, Tokyo Institute of Technology.
Abstract
We study the dynamical fidelity and the Loschmidt echo, following a periodic driving of the transverse magnetic field of a quantum Ising chain (across the quantum critical point) which is calculated through the overlap between the initial ground state and the state reached after n periods (calculated using the Floquet theory). We show that the logarithm of the fidelity per-site reaches a steady value in the asymptotic limit of n, and we derive an exact analytical expression for this quantity. Remarkably, unlike thermodynamic quantities such as energy and transverse magnetization, the steady state value of logarithm of the fidelity per-site cannot be derived by using a decohered density matrix, and keeps memory of non-trivial phase information.
Contact
Prof. Hidetoshi Nishimori (2488)
Lecture materials
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