Spring 2018

Tunable Berry Phase and Berry Curvature Effects in 2D and 3D Materials

Long Ju
Monday, January 22, 2018 - 4:30pm to 5:30pm

Berry phase played an important role in quantum mechanics and underlying the physics of a wide range of materials from topological phases of matters to various 2D materials. While the effect of Berry phase has been extensively studied and shown through quantized electron transport experiment, the geometric aspect of wavefunction— determined by Berry curvature has remained much less understood experimentally. In this talk, I will use bilayer graphene as a model system to demonstrate effects of Berry phase and Berry curvature on materials’ electronic and optical...

Professor Emeritus Edward Gerjuoy Publishes Paper on Julian Schwinger

  • By Burcu Ozden
  • 12 January 2018

An article by PQI member Edward Gerjuoy will be included in a book titled "Memories of Julian Schwinger" in a new edition of Schwinger's book Quantum Mechanics - Symbolism of Atomic Measurements (Springer, 2018), published for the centennial of Schwinger's birth. Schwinger, who shared the 1965 Nobel Prize in Physics with Richard Feynman and Sin-Itiro Tomonaga for the invention of quantum electrodynamics, was a classmate of Gerjuoy's at City College of New York in the 1930s. Gerjuoy noted that he had a better grade in classical mechanics than Schwinger did.

Coupling superconducting qubits and mechanics: A path to quantum communication?

Andrew Cleland
Monday, April 16, 2018 - 4:15pm

Superconducting qubits offer excellent prospects for manipulating quantum information, with good qubit lifetimes, high fidelity single- and two-qubit gates, and straightforward scalability (admittedly with multi-dimensional interconnect challenges). One interesting route for experimental development is the exploration of hybrid systems, i.e. coupling superconducting qubits to other systems. I will report on our group's efforts to develop approaches that will allow interfacing superconducting qubits in a quantum-coherent fashion to mechanical resonators and to optomechanical devices. The...

Interfacial Engineering of Quantum Materials

Shuolong Yang
Monday, January 29, 2018 - 3:00pm to 4:00pm

Quantum materials are fascinating platforms where macroscopic quantum phenomena occur. As a prominent example, superconductors conduct electricity with no dissipation at low temperatures, holding great promise to address global energy challenges. It is of tremendous scientific and technological interest to enhance superconducting transition temperatures. In this talk I will elucidate the principles of interfacial engineering and co-operative interactions through studies of bulk superconductors, and demonstrate how I implement these concepts in fabricating an iron selenide/strontium...

Quantum Measurements in Cavity Optomechanics

Thomas Purdy
Thursday, February 1, 2018 - 4:00pm to 5:00pm

Over the last several years, research in the field of cavity optomechanics has developed extraordinarily sensitive and low loss devices as well as clever measurement techniques to probe macroscopic mechanical systems in the quantum regime.  If one observes carefully, the noise in optically detected mechanical resonators can reveal a remarkable tale of the fundamental quantum mechanics of measurement embodied by Heisenberg’s microscope type physics.  In this talk, I will review the basic consequences of quantum measurement backaction in the context of recent cavity optomechanics experiments...

Quantum LEGOs: Building large quantum systems atom-by-atom

Hannes Bernien
Monday, February 5, 2018 - 3:00pm to 4:00pm

The realization of large-scale controlled quantum systems is an exciting frontier in modern physical science. In this talk, I will introduce a new approach based on cold atoms in arrays of optical tweezers. We use atom-by-atom assembly to deterministically prepare arrays of individually controlled cold atoms. A measurement and feedback procedure eliminates the entropy associated with the probabilistic trap loading and results in defect-free arrays of over 60 atoms [1]. Strong, coherent interactions are enabled by coupling to atomic Rydberg states. We realize a programmable Ising-type...