Time-resolved observation of spin-charge deconfinement in fermionic Hubbard chains

January 10, 2020

Elementary particles carry several quantum numbers, such as charge and spin. However, in an ensemble of strongly interacting particles, the emerging degrees of freedom can fundamentally differ from those of the individual constituents. For example, one-dimensional systems are described by independent quasiparticles carrying either spin (spinon) or charge (holon). Here, we report on the dynamical deconfinement of spin and charge excitations in real space after the removal of a particle in Fermi-Hubbard chains of ultracold atoms.

Floquet approach to Z2 lattice gauge theories

September 20, 2019

Strongly-interacting gauge theories are extremely challenging to access with conventional numerical techniques. Here, we take a first step towards quantum simulation of gauge theories by implementing a Floquet-based method with two-component ultracold bosons in a double-well potential. For resonant periodic driving at the on-site interaction strength and an appropriate choice of the modulation parameters, the effective Floquet Hamiltonian exhibits Z2 symmetry.

Many-Body Delocalization in the Presence of a Quantum Bath

October 18, 2019

Some isolated quantum systems with disordered potentials fail to ever reach thermal equilibrium, a phenomenon known as many-body localization (MBL). An outstanding question concerns the stability of this phenomenon. While it is well known that exposing the quantum system to the outside world destroys localization, it is not clear what happens when the MBL system is connected to another small quantum system known as a quantum bath. Does a quantum bath destroy the localization, and if so, how small can that bath be?

Imaging magnetic polarons in the doped Fermi-Hubbard model

August 14, 2019

Here we report the microscopic real-space characterization of magnetic polarons in a doped Fermi–Hubbard system, enabled by the single-site spin and density resolution of our ultracold-atom quantum simulator. We reveal the dressing of doublons by a local reduction—and even sign reversal—of magnetic correlations, which originates from the competition between kinetic and magnetic energy in the system. The experimentally observed polaron signatures are found to be consistent with an effective string model at finite temperature.


Group Seminar at MPQ: Quantum nonlinear optics using 2D atomic arrays

February 10, 2020

Darrick Chang, ICFO Barcelona
MPQ Garching, Hans-Kopfermann-Str. 1
Herbert-Walther lecture hall
Monday, February 10, 10:15 am

Group Seminar at LMU: Building a collective quantum memory using quantum dots

January 28, 2020

Clara Bachorz, Imperial College
LMU München, Schellingstr. 4
Seminar room H 107
Tuesday 01/28, 09:15

Group Seminar at LMU: Quantum Sensing Using NV Centers in Diamond

January 14, 2020

Tim Höhn
LMU München, Schellingstr. 4
Seminar room H 107
Tuesday 01/14, 09:15am

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