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[Fizinfo] Szemináriumok - Seminars: Andrea Alberti

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  • From: Szeminárium koordinátor <szfi-seminar AT>
  • To: SZFI Szeminárium <seminar AT>,Fizinfo <fizinfo AT>
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  • Subject: [Fizinfo] Szemináriumok - Seminars: Andrea Alberti
  • Date: Tue, 3 Sep 2019 06:26:02 +0200 (CEST)
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SZFI SeminarAndrea AlbertiUniversitaet Bonn (host: Asbóth János)Controlling
atomic wave packets at the quantum speed limitTuesday, 3 September 2019,
10:00, KFKI Campus, Bldg. 1, 2nd floor, Conference RoomI will report on the
experimental realization of fast, high-fidelity transport of atomic wave
packets in deep optical lattices. The goal here is to transport atoms by one
or more lattice sites in the shortest time allowed by quantum mechanics,
under the constraint that no motional excitation is created after transport,
and the optical lattice depth does not exceed a maximum value given by the
available resources (e.g., finite laser power). To achieve fast atom
transport, we use quantum optimal control, which allows several motional
excitations to be created during the transport process, and yet refocus them
back into the motional ground state with a fidelity at around 99%. Optimizing
the process for various transport times, we clearly observe a minimum time
below which transport operations unavoidably create motional excitations.
This time defines the quantum speed limit for the transport operation. From
the experimental data, we deduce that such a minimal transport time is
essentially determined by the harmonic period of the trapping potential.
Theoretically, such a time can be estimated using the energy uncertainty and
the Fubini-Study metric quantifying the path length connecting the initial
and final states. I will show that the fast atom transport in spin-dependent
optical lattices allows us to outrun decoherence, and thus to improve
coherence of Mach-Zehnder atom interferometers and of quantum-walk
experiments, where atoms are delocalized in space through a multiplicity of
quantum paths. Finally, I will conclude with an outlook towards
two-dimensional quantum-walk experiments for the study of anomalous Floquet
Chern topological insulators using pseudo spin-1/2 particles [1].[1] Sajid et
al., “Creating anomalous Floquet Chern insulators with magnetic quantum
walks” Phys. Rev. B 99, 214303 (2019).&nbsp;Minden érdeklődőt szívesen
látunk! - Everyone is welcome to attend.Róbert
Juhászszfi-seminar AT

  • [Fizinfo] Szemináriumok - Seminars: Andrea Alberti, Szeminárium koordinátor, 09/03/2019

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