Seminar Schedule

Find upcoming seminars below. All talks are also announced via our mailing list and are also available via a google calendar (ical). Previous talks as well as a copy of the slides will be made available for the foreseeable future on the VIDEOS page.

Thu 2021-01-21 17:00 CET

Quantum Science Seminar #32: Quasicrystals
Ulrich Schneider
University of Cambridge
Cambridge — U.K.
Optical Quasicrystals—Quantum Simulations beyond periodic systems
Quasicrystals are an intriguing form of condensed matter that is not periodic, but nonetheless long-range ordered. They can be described as self-similar, fractal structures containing more than one type of unit cell, similarly to the celebrated Penrose tiling. Despite them being long-range ordered like a crystal, many foundational concepts of periodic systems such as Bloch waves or Brillouin zones are not applicable. This peculiar situation enables new physics including fractal band structures, many-body localization, phasonic degrees of freedom, and an intriguing direct link to higher dimensions.
I will present our experimental realization of an eightfold symmetric optical quasicrystal for ultracold atoms and demonstrate how matterwave diffraction directly reveals the self-similar fractal nature of this potential and realizes continuous quantum walks in up to four synthetic dimensions. I will also present the localization transition in these potentials and close with an outlook on realizing many-body localization and the so-far elusive 2D Bose glass in these potentials.

Thu 2021-01-28 17:00 CET

Quantum Science Seminar #33: Young Researchers
Jessie Zhang
Harvard University
Cambridge — Massachusetts — U.S.A.
Assembly of a single rovibrational ground state molecule in an optical tweezer
Ultracold molecules hold promise for various quantum science applications that could utilize their long-range dipole-dipole interactions and rich internal structures. Trapping and manipulating molecules in optical tweezers offer many advantages due to their high level of controllability. In this talk, I will discuss our recent results in forming a single NaCs molecule in its rovibrational ground state starting from a pair of atoms in an optical tweezer. This is achieved by first magnetoassociating into a Feshbach molecule and then applying a Raman pulse which gives rise to coherent Rabi oscillations between the ground state. Our work opens up exciting possibilities with fully quantum-state-controlled molecules in optical tweezer arrays.
Ryan MacDonnell
University of Sydney
Sydney — Australia
Analog quantum simulation of chemical dynamics
Quantum chemical simulation is a challenging task for classical computers due to the rapid growth of information with system size. Quantum computing techniques may alleviate this issue, but to date demonstrations have been limited to static properties of small systems. We show how analog quantum simulation can be used to study chemical dynamics governed by vibronic coupling Hamiltonians. Our approach uses an optimal, linear mapping of vibrational modes and electronic states of the molecule onto bosonic modes and internal states of the simulator. In addition, we show how our approach readily extends to large, open-quantum systems, all using existing technology.
Gonzalo Carvacho
Sapienza Università di Roma
Rome — Italy
Experimental violation of n-locality in a star quantum network
Nonlocality in networks with independent entanglement sources has only been experimentally verified in simple tripartite networks, via the violation of bilocality inequalities. Here, by using a scalable photonic platform, we implement star-shaped quantum networks consisting of up to five distant nodes and four independent entanglement sources. We exploit this platform to violate the chained n-locality inequality and thus witness, in a device-independent way, the emergence of nonlocal correlations among the nodes of the implemented networks. These results open new perspectives for quantum information processing applications.