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Tesi etd-06302021-155512


Tipo di tesi
Tesi di laurea magistrale
Autore
TARANTELLI, FRANCESCO
URN
etd-06302021-155512
Titolo
Quantum critical behavior in the presence of dissipative boundaries
Dipartimento
FISICA
Corso di studi
FISICA
Relatori
relatore Prof. Vicari, Ettore
Parole chiave
  • dissipative boundaries
  • finite size scaling
  • Kitaev model
  • open quantum systems
  • quantum transitions
Data inizio appello
22/07/2021
Consultabilità
Completa
Riassunto
We study the effects of dissipative boundaries in many-body systems at continuous quantum transitions, when the parameters of the Hamiltonian driving the unitary dynamics are close to their critical values. As paradigmatic models, we consider fermionic wires subject to dissipative interactions at the boundaries, associated with pumping or loss of particles. They are induced by couplings with a Markovian baths, so that the evolution of the system density matrix can be described by a Lindblad master equation. We study the quantum evolution arising from variations of the Hamiltonian and dissipation parameters, starting at t=0 from the ground state of the critical Hamiltonian. Two different dynamic regimes emerge: (i) an early-time regime for times t~L, where the competition between coherent and incoherent drivings develops a DFSS, obtained by extending the scaling framework describing the coherent critical dynamics of the closed system, to allow for the boundary dissipation; (ii) a large-time regime for t~L^3 whose dynamic scaling describes the late quantum evolution leading to the stationary states.
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