JQI Seminar

Abstract: Do p-wave systems have universal properties? Ultracold atoms are normally dominated by s-wave interactions, because scattering channels with orbital angular momenta must tunnel through a centrifugal barrier. However, femionic exchange symmetry and Feshbach resonances have been shown to enhance p-wave scattering. In this talk, I will discuss recent work that also uses strong confinement to control orbital interactions in spin-polarized Potassium 40. Spectroscopy of isolated atom pairs reveals multi-branched unitary interactions, enabling a test of the p-wave pseudopotential.

Abstract: A pedagogical review will be given on quantum scaling anomalies and its consequences in 2D and 1D systems. The emphasis will be in the concepts and the basic logic of the main applications of these ideas to the study of ultracold, diluted Fermi systems. The impact of these developments in other areas will be presented.

Abstract: Quantum systems with a flexible architecture of connections and interactions mimic natural systems and provide an interesting arena to study thermodynamic evolution. In this talk I will introduce the minimum size of a machine of thermally initialized qubits that can generate an increase in extractable work for a subsystem and then embed the machine dynamics into a larger landscape of qubits.

Abstract: Degenerate gases in modulated optical lattices are a flexible testbed for the experimental study of quantum matter driven far from equilibrium. I will present results from a sequence of recent experiments in this area, on topics ranging from interacting quantum kicked rotors to localization in driven quasicrystals. Time permitting, I will also discuss a new tweezer-based degenerate gas platform under construction at UC Santa Barbara which aims at the study of quantum interactive dynamics.

Abstract: It is interesting to observe that all known optical materials have a refractive index that is of order unity at visible/telecom wavelengths. However, it is not easy to reconcile this with the fact that the individual atoms making up the material are well-known to have a huge optical response near resonance, when isolated, as characterized by a scattering cross section that is much larger than the physical size of the atom.

Abstract: Quantum memories using cold and ultracold atoms are a promising platform for storing and manipulating photonic signals, and will be a key component in quantum communications systems, especially in realizing critical quantum repeater infrastructure. Cold atoms have significant potential as high performance spin-wave quantum memories, due to the long storage times associated with low temperature and slow thermal diffusion. Broadband, low-noise performance in such memories is also required, but these two principles are often at odds with each other.

Abstract: Spin glasses are canonical examples of complex matter.  Although much about their structure remains uncertain, they inform the description of a wide array of complex phenomena, ranging from magnetic ordering in metals with impurities to aspects of evolution, protein folding, climate models, and artificial intelligence, where spin glass theory forms a mathematical basis for neuromorphic computing.

Abstract: Why does the Army care about quantum mechanics?  In this JQI Seminar, Dr. Kevin Cox will discuss what it's like to be a physicist at the Army Research Laboratory and talk about how his group is using Rydberg atoms to create radio-frequency receivers that can sense the entire spectrum.

*You will need to bring your cell phone, so you can sign in.  For Zoom, please submit a chat saying hello with your first and last name, so you can receive lunch.  Lunch will be served after the seminar only to the individuals that have attended.*

Abstract: Experiments with ultracold gases and digital quantum simulators can take simultaneous snapshots of all the particles in a system. Unlike conventional response experiments, these snapshots encode arbitrarily high-order correlation functions. It is natural to ask what new information these high-order correlations contain. I will present solvable models, as well as experimental data, showing how these new probes can elucidate (and disprove) certain proposed mechanisms for many-body dynamics.

Abstract: We construct a Pauli stabilizer model for every Abelian topological order that admits a gapped boundary in two spatial dimensions. Our primary example is a Pauli stabilizer model on four-dimensional qudits that belongs to the double semion (DS) phase of matter. The DS stabilizer Hamiltonian is constructed by condensing an emergent boson in a Z4 toric code. We show that the construction of the DS stabilizer Hamiltonian generalizes to all twisted quantum doubles (TQDs) with Abelian anyons.