Prof. Lea Ferreira dos Santos, Department of Physics, University of Connecticut

Nonequilibrium Quantum Dynamics

Santos’s group uses numerical and analytical methods to understand, predict, and control the dynamics of quantum systems taken far from equilibrium. This talk will present two lines of research of the group. (i) The characterization of quantum systems with many interacting particles, the timescales for their relaxation process, and the conditions for reaching thermal equilibrium. (ii) The use of the quantum-classical correspondence to better understand and make use of static and dynamical properties of transmon qubits, which are the predominant element in circuit-based quantum information processing.

Prof. Wenchao Ge, University of Rhode Island

How to Make a Faster Trapped-Ion Quantum Computer?

Trapped ions offer a pristine platform for quantum computation, but enhancing the interactions without compromising the qubits remains a crucial challenge. In this talk, I will present a strategy to enhance the interaction strengths in trapped-ion systems via parametric amplification of the ions’ motion, thereby suppressing the relative importance of decoherence. We illustrate the power of this approach by showing how it can improve the speed and fidelity of two-qubit gates in multi-ion systems and how it can enhance collective spin states useful for quantum metrology. Our proposal has been further demonstrated in the experiment, confirming the enhancement. Our results open a new avenue of phonon modulation in trapped ions and are directly relevant to numerous other physical platforms in which spin interactions are mediated by bosons.

Prof. Peter Schweitzer, Department of Physics, University of Connecticut

Internal Structure of Hadrons

Hadrons are composed particles and exhibit a rich internal structure which is probed experimentally in high energy experiments and described in the theory of Quantum Chromodynamics. Recent advances in the theory of hadron structure with focus on gravitational form factors are discussed.

Dr. Eric Koch, Harvard Smithsonian Center for Astrophysics

Revealing the multi-phase neutral interstellar medium’s role in the star formation lifecycle: a sharpened view of nearby galaxies from LGLBS and PHANGS-JWST

The neutral interstellar medium (ISM) fuels the star formation lifecycle, yet we still lack vital constraints on the formation and destruction of molecular clouds because of challenges in observing the cold neutral ISM phases with high resolution and sensitivity. With dedicated surveys, the combination of VLA, ALMA, and JWST can now make significant advances in the coming years. In this talk, I will present multiple observational approaches that are making progress in this area: detailed 21-cm HI VLA mapping across the Local Group from the Local Group L-band Survey (lglbs.org), resolved molecular cloud studies with ALMA and JWST in M33 and PAH imaging from PHANGS-JWST as a highly sensitive resolved view of the total neutral gas tracer (phangs.org). These surveys bridge Galactic with extragalactic star formation studies and provide new constraints to guide the next generation of numerical simulations.

The Physics Department ice cream social

will take place on Friday, September 27th at 1:30 in Gant South 117.

All are welcome!

Prof. Simone Colombo, Department of Physics, University of Connecticut

Observing our Universe with Quantum Sensors

In this seminar, we will introduce the application of atomic, molecular, and optical (known as AMO) physics to the field of quantum metrology. We will show how atoms are used as probes of our universe and how to harness quantum effects to enhance their sensing capabilities.

We will then focus on a specific type of atomic sensor and one of our research interests: optical atomic clocks. Building upon recent results, we will illustrate how optical clocks’ performances can be pushed beyond current limitations and how they can be/are deployed to get a better glimpse of the inner workings of our universes. In this framework, we will highlight the research activities that we are currently pursuing in our lab. Crucially, we will attempt to give a perspective on the life of an AMO physicist.

Prof. Nikolay Prokofiev, UMass Amherst

Bi-polaron superconductivity in the low density limit

It has been assumed for decades that high values of Tc from the electron-phonon coupling are impossible. At weak-to-intermediate coupling strength this result follows from the Migdal-Eliashberg theory, while at strong coupling, when bipolarons form, the transition temperatures are low because of the exponential effective mass enhancement. However, the latter conclusion was based on numerical solutions of the Holstein model. I will discuss a different model with coupling based on the displacement modulated hopping of electrons and argue that much larger values of the bipolaron Tc can be achieved in this setup. Non-locality of the problem gives rise to small-size, yet relatively light bipolarons, which can be studied by an exact sign-problem-free quantum Monte Carlo approach even in the presence of strong Hubbard and Coulomb potentials. We find that Tc in this model generically and significantly exceeds typical upper bounds based on Migdal-Eliashberg theory or superfluidity of Holstein bipolarons, and, thus, offers a route towards the design of high-Tc superconductors via functional material engineering. Finally, there are indications for even better prospects in systems with non-linear electron-phonon coupling.