• Abstract

Rydberg and molecule level landscapes: From synthetic dimensions to exotic particle statistics

ABSTRACT: Both Rydberg atoms and molecules in tweezer arrays have provided revolutionary capabilities in quantum science, enabled by their long-range dipolar interactions. I will describe our research that has begun to explore the vast possibilities opened by using the plentiful internal states of these systems (Rydberg levels or rotational states) coupled via microwave fields. These have allowed experiments to create large-spin models and systems with extra "synthetic dimensions," where the internal degrees of freedom mimic motion in a fully-controlled extra spatial dimension. I will describe some of the novel many-body physics that can occur. One particularly interesting direction is that these systems can host excitations that are described by particle exchange statistics neither bosonic nor fermionic, nor confined to two-dimensions (as for anyons), in contrast to the long-held wisdom that fermionic and bosonic statistics are the only possible statistics in our three-dimensional universe.   

BIO: Dr. Hazzard theoretically studies the behavior of ultracold atomic systems.He is interested in “emergent” properties of many-body systems, and pursues this phenomenon in ultracold gases. The vision is that fundamental advances in controlling, measuring, and understanding these many-body quantum systems will impact knowledge of other fields through “quantum simulation”, broadly construed, and enable applications in quantum metrology, precision measurement, and quantum computation.
He attended the Ohio State University for his bachelor’s degree and earned his PhD from Cornell University, working with Erich Mueller in 2010. After working 2010-14 as a postdoc at JILA with Ana Maria Rey, he joined Rice University’s physics and astronomy faculty.

• Abstract

Spin squeezing in an ensemble of nitrogen-vacancy centers in diamond

Spin squeezed states provide a seminal example of how the structure of quantum mechanical correlations can be controlled to produce metrologically useful entanglement. Such squeezed states have been demonstrated in a wide variety of artificial quantum systems ranging from atoms in optical cavities to trapped ion crystals. By contrast, despite their numerous advantages as practical sensors, spin ensembles in solid-state materials have yet to be controlled with sufficient precision to generate targeted entanglement such as spin squeezing. In this work, we present the first experimental demonstration of spin squeezing in a solid-state spin system. Our experiments are performed on a strongly-interacting ensemble of nitrogen-vacancy (NV) color centers in diamond at room temperature and squeezing (-0.5 pm 0.1 dB) is generated by the native magnetic dipole-dipole interaction between NVs. In order to generate and detect squeezing in a solid-state spin system, we overcome a number of key challenges of broad experimental and theoretical interest. First, we develop a novel approach, using interaction-enabled noise spectroscopy, to characterize the quantum projection noise in our system without directly resolving the spin probability distribution. Second, noting that the random positioning of spin defects severely limits the generation of spin squeezing, we implement a pair of strategies aimed at isolating the dynamics of a relatively ordered sub-ensemble of NV centers. Our results open the door to entanglement-enhanced metrology using macroscopic ensembles of optically-active spins in solids.

Bio: Emily J. Davis earned her PhD in the lab of Monika Schleier-Smith at Stanford University. There, she built a cavity QED experiment to study nonlocal spin models. She subsequently completed postdoctoral work as a Miller Research Fellow hosted by Norman Yao at UC Berkeley, where she explored many-body dynamics and metrology using ensembles of solid-state spins. She is currently an assistant professor in the Center for Quantum Phenomena at New York University. 

• Abstract

Scattering in a Bose-Einstein condensate with multiple momentum components

Atomic Bose-Einstein condensates (BECs) are typically dilute and characterized by a condensate fraction close to 100%. The correlated, beyond mean-field quantum regime, where the condensate fraction can be significantly reduced, has been realized in a number of ways such as by tuning the s-wave scattering length to a large, in magnitude, value; by loading a dilute Bose gas into an optical lattice; by working with spinor BECs; and by periodically modulating the lattice or the s-wave scattering length of an inhomogeneous BEC. This talk reports on the appearance of quantum scattering spheres due to atom-atom scattering processes that are facilitated by preparing the Bose gas in an initial superposition state of two macroscopically occupied momentum states. Lattice coupling and Raman coupling schemes are considered and compared.

BIO: Doerte received her Ph.D. in physics in 1998 from the Georg-August University, Goettingen, Germany. Her research was jointly supervised by Profs. Jan Peter Toennies at the Max-Planck Institute for Fluid Dynamics in Goettingen, Germany, and K. Birgitta Whaley in the Chemistry Department at UC Berkeley. After 2.5 years of postdoctoral work at JILA/University of Colorado in Boulder in the group of Prof. Chris Greene, she took up a faculty position in the Department of Physics and Astronomy at Washington State University in the beautiful inland Northwest. In the summer of 2017, Doerte relocated to the Homer L. Dodge Department of Physics and Astronomy at the University of Oklahoma. Doerte is a Fellow of the American Physical Society; the citation reads “For contributions to physics of weakly-bound quantum clusters and strongly-interacting degenerate Fermi gases in one dimension.” She is a recipient of a Bush Lectureship at the University of Oklahoma and a Meyer Distinguished Professorship at Washington State University. Her research accomplishments at Washington State University were also recognized through the College of Arts and Sciences Mid-Career Achievement in Scholarship/Creative Activities Award and the College of Sciences Young Faculty Performance Award. Doerte has given over 150 invited talks at universities, summer/winter schools, and workshops/conferences around the world. She regularly co-organizes conferences of varying size, including the Conference for Undergraduate Women in Physics in 2020. In addition, she has served the scientific community as a member of the DAMOP Executive Committee, Remote Associate Editor of Physical Review A, Chair of the APS Few-Body Topical Group, and member of the APS Committee on Scientific Publications.

• Abstract

Maxwell and Schrödinger Matter Waves

ABSTRACT: Maxwell equations teach us that alternating electric currents give rise to electromagnetic waves, and that generally the behavior of AC currents can be quite different than the behavior of direct (DC) currents.  The formal treatment of alternating currents of neutral atoms surprisingly leads to a set of matter-wave duals to Maxwell’s equations. These duals, though, have properties that are importantly different from the electromagnetic versions in unintuitive ways.  Moreover, unexpected behavior arises in the mechanics of AC matter waves, such as substantial tunneling through barriers that occurs even at low particle energy.   I will provide a deeper look at the nature of and relationship between DC matter waves, which are the familiar solutions to Schrödinger’s equation, and their AC cousins that are described by Maxwell-like wave equations.  I will also briefly discuss the utility that AC matter waves can bring to practical systems, such as atom-based sensors.

BIO: Prof. Dana Z. Anderson received in Ph.D. in quantum optics working under Prof, Marlan Scully. His thesis research centered on fundamental principles of ring laser gyroscopes. As a postdoctoral fellow at Caltech he carried out work on the prototype laser interferometer gravitational observatory (LIGO). He is currently a Fellow of the JILA Institute at the University of Colorado and a Professor of the Department of Physics and the Department of Electrical, Computer and Energy and Engineering at the University. He is an applied physicist working in the areas of quantum optics, atomic physics, and precision measurement. His research includes the development of atom based inertial sensors, quantum communications systems, quantum computing, quantum emulators, and atomtronics (the atom analog of electronics). Prof. Anderson has published over 100 refereed papers, holds several patents, and has received several awards including a Presidential Young Investigator award, a Sloan Foundation Fellowship, a Humboldt Research Award, the Optical Society of America’s R.W. Wood Prize for his pioneering work on optical neural networks, the CO-LABS Governor’s Award for foundational contributions ultracold matter technology, and the Willis Lamb Prize for Excellence in Quantum Optics and Electronics.
Prof. Anderson is also Founder and CTO of Infleqtion, formerly ColdQuanta, Inc., a company that develops and manufactures cold and ultracold matter-based quantum technology covering a broad spectrum of systems, from clocks to quantum computers, including a system currently operating on the International Space Station under NASA’s Cold Atom Laboratory (CAL) mission.

• Abstract

Controlling and probing quantum correlations in superconducting circuits

Abstract:
Superconducting circuits provide a versatile platform for exploring many-body physics in synthetic quantum matter. To advance scalable quantum simulation using circuit devices, I will present our recent progress in developing efficient techniques for controlling and measuring quantum correlations and dynamics. We engineer tunable driven-dissipative baths and apply them in coupled superconducting qubit arrays to autonomously stabilize entangled states. Additionally, we investigate how collective qubit decay can be harnessed and combined with coherent control to generate quantum correlations in qubit lattices. To characterize the resulting many-body states, we demonstrate the measurement of in-situ particle current and current statistics, as well as site-resolved tunneling spectroscopy using the tunable baths as tunneling probes. We apply these tools to probe quantum transport and phase transitions in a circuit Bose-Hubbard lattice.

Bio: Alex Ruichao Ma received his Ph.D. in Physics from Harvard University in 2014, where he studied many-body physics using ultracold atoms in optical lattices. From 2015 to 2019, he worked on superconducting qubits for quantum simulation as a Kadanoff-Rice Postdoctoral Fellow at the James Franck Institute, University of Chicago. In 2019, Alex joined Purdue University as an Assistant Professor in the Department of Physics and Astronomy. His experimental group focuses on quantum many-body physics and quantum information science using superconducting circuits. He is a recipient of the NSF CAREER Award in 2022.