Characterization of a quantum phase transition in Dirac systems by means of the wavepacket dynamics

We study the signatures of phase transitions in the time evolution of wave-packets by analyzing two simple model systems: a graphenequantum dot model in a magnetic field and a Diracoscillator in a magnetic field. We have characterized the phase transitions using the autocorrelation function. Our work also reveals that the description in terms of Shannon entropy of the autocorrelation function is a clear phase transition indicator.This work was supported by Spanish MICINN projects FIS2011-24149 and FIS2009-08451, CEI BioTic UGR project 20F12.41 and Junta de Andalucia projects FQM-165/0207 and FQM219

Identifying wave packet fractional revivals by means of information entropy

Wave packet fractional revivals is a relevant feature in the long time scale evolution of a wide range of physical systems, including atoms, molecules and nonlinear systems. We show that the sum of information entropies in both position and momentum conjugate spaces is an indicator of fractional revivals by analyzing three different model systems: $(i)$ the infinite square well, $(ii)$ a particle bouncing vertically against a wall in a gravitational field, and $(iii)$ the vibrational dynamics of hydrogen iodide molecules. This description in terms of information entropies complements the usual one in terms of the autocorrelation function

Phase-space Fisher information of 2D gapped Dirac materials

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Quantum recurrence times in nanostructures

We compute the classical and revival times of electron currents in several bulk nanostructured, semiconductor materials. We have used a nonparabolic Schrödinger equation to model the conduction band of semiconductors. We have calculated the classical and revival periods for quantum dots of Si, Ge and InAs quantum dots. The obtained results are of the order of tenths of nanoseconds to picoseconds, which are within reach of current technologies.This work is part of the Project of I+D+i Ref. PID2020-113681GB-I00, financed by MICIN/AEI/10.13039/501100011033 and FEDER “A way to make Europe”

Identifying the order of a quantum phase transition by means of Wehrl entropy in phase space

We propose a method to identify the order of a quantum phase transition by using area measures of the ground state in phase space. We illustrate our proposal by analyzing the well known example of the quantum cusp and four different paradigmatic boson models: Dicke, Lipkin-Meshkov-Glick, interacting boson model, and vibron model.We thank J. E. Garcia Ramos for useful discussion. Work in University of Huelva was funded trough MINECO Grants No. FIS2011-28738-C02-02 and No. FIS2014-53448-C2-2-P and by Spanish Consolider-Ingenio 2010 (Grant No. CPANCSD2007-00042). Work in University of Granada was supported by the Spanish Projects: MINECO Grant No. FIS2014-59386-P and Junta de Andalucia Projects No. P12.FQM.1861 and No. FQM-381