【时   间】 3-Nov-2023（Friday）10:00am (Beijing time)

【地   点】 量子院526会议室

【报告人】 Prof. Mariusz Gajda （Institute of Physics Polish Academy of Sciences, Warsaw, Poland）

【主持人】 Li You (Tsinghua University & BAQIS）

【题    目】Time-continuous measurement of position and momentum of a quantum particle

【摘  要】In my talk I will present a model of frequently repeated measurement of position and momentum of a quantum particle. I will shortly discuss the measurement problem in quantum mechanics. Then I will formulate an open system formalism suited for description of a particle interrogated by a grid of detectors distributed uniformly in the phase space. The formalism incorporates a wavefunction collapse postulate: after a measurement the system is assumed to be in one of a meter’s state which is a coherent state of a local quantum oscillator. Trajectories of observables are generated using Wave Function Quantum Monte Carlo method.  Some simple illustrative examples will be given. The Zeno effect, for a relatively sparse spatial grid of detectors, as well as emergence of classical trajectories, for densely distributed meters, will be discussed. Analogy to classical dynamics of a particles subject to the Brownian motion will be pointed out.

【报告人简介】Mariusz Gajda, Institute of Physics Polish Academy of Sciences, Warsaw, Poland. Presently work at the Institute of Physics, Polish Academy of Sciences.

I got my PhD presenting the thesis: Light scattering by trapped ions, under supervision of Jan Mostowski in 1985. At the early stages of my scientific carrier I worked on problems related to interaction of atoms with ultra-strong e-m field and stabilization phenomenon.  I spent two years as post-doc at the Department the Physics of the University of Arizona in Tucson.  I received the professor title from the president of Poland in 2011.

 Most of my work is related to the theory of ultra-cold degenerate atomic quantum gases: fluctuations of a BEC, creation of vortices, description of a BEC at non-zero temperature, to this end I formulated with K. Rz??ewski the classical fields method. Then I studied spinor and dipolar condensates, lattice models, quantum droplets in a Bose-Bose and Bose-Fermi mixtures. I was a visiting professor at Paris Sorbonne University – Paris Nord XIII, collaborating with prof. Bruno Laburthe-Tolra.  I also collaborated with ICFO group of prof. M. Lewenstein.