Seminar

In this talk, I present an experimental realization of a quantum absorption refrigerator formed from superconducting circuits. The refrigerator is used to reset a transmon qubit to a temperature lower than that achievable with any one available bath. The process is driven by a thermal gradient and is autonomous -- requires no external control. The refrigerator exploits an engineered three-body interaction between the target qubit and two auxiliary qudits coupled to thermal environments, formed from microwave waveguides populated with thermal photons.

In this seminar, we are interested in all aspects of research at the intersection between quantum information science and mathematics. Goals for the seminar include:

Universal behaviors of nonequilibrium quantum many-body systems may be usefully captured by the dynamics of quantum information measures. Notably, the dynamics of bipartite entanglement entropy can distinguish integrable quantum systems from chaotic ones. The two most successful effective theories describing the evolution of entanglement from a low-entangled initial state are the quasiparticle picture and the membrane picture, which provide distinct predictions for integrable and chaotic systems, respectively.

Aleksander Kubica, Assistant Professor at Yale University and former Research Scientist at AWS will give a career talk on his experiences in both industry and academia, present a short lecture on quantum chess, and take questions from the audience.  

A key objective in nuclear and high-energy physics is to describe nonequilibrium dynamics of matter, e.g., in the early universe and in particle colliders, starting from the Standard Model. Classical-computing methods, via the framework of lattice gauge theory, have experienced limited success in this mission. Quantum simulation of lattice gauge theories holds promise for overcoming computational limitations. Because of local constraints (Gauss's laws), lattice gauge theories have an intricate Hilbert-space structure.

In this Career Connections talk, Dr. Mihir Bhaskar (CEO and Co-Founder of Lightsynq) will share insights from his career journey: first building a science experiment in the lab as a PhD student, then moving to AWS to launch a new R&D initiative, and finally starting a quantum technology company to build a product. He will also talk about the integrated photonic capabilities his team has developed along the way, and how he thinks they can solve key bottlenecks in quantum information technology.

We introduce parallel-sequential (PS) circuits, a family of quantum circuits characterized by a tunable degree of entanglement and maximum correlation length, which interpolates between brickwall and sequential circuits. We provide evidence that on noisy devices, properly chosen PS circuits suppress error proliferation and exhibit superior trainability and evaluation accuracy when employed as variational circuits, thus outperforming brickwall, sequential, and log-depth circuits in [Malz*, Styliaris*, Wei*, Cirac, PRL 2024] across most parameter regimes.

Abstract: This talk will review our recent work on classical and quantum glasses. I will start with a discussion of spin glasses from the perspective of chaos theory.

Error-correction is key to building a quantum computer. This includes both storage of quantum information as well as computing on it. Quantum low- density parity check (LDPC) codes offer a route to build these devices with low space overhead. The next question is - how do we fault-tolerantly com- pute on these codes?  Existing proposals (Cohen et al. [2110.10794], Cross et al. [2407.18393]) rely on ancilla systems appended to the original LDPC code.

Characterizing higher-order interactions in quantum processes with unknown Hamiltonians presents a significant challenge. This challenge arises, in part, because two-body interactions can lead to an arbitrary evolution, and two-local gates are considered universal in quantum computing. However, recent research has demonstrated that when the unknown Hamiltonian follows a U(1) symmetry, like charge or number conservation, N-body interactions display a distinct and symmetry-protected feature called the N-body phase.