JQI

Abstract: A cryptographic proof of quantumness is a hypothetical test that could be used to prove a quantum computational advantage based on hardness assumptions from cryptography.  An experimental realization of such a test would be a major milestone in the development of quantum computation.  However, error tolerance is a persistent challenge for implementing such tests: we need a test that not only can be passed by an efficient quantum prover, but one that can be passed by a prover that exhibits a certain amount of computational error.

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.  

Abstract: I'll give theorems characterizing finite-dimensional quantum theory's framework of 

Abstract: We extend entropy production to a deeply quantum regime involving noncommuting conserved quantities. Consider a unitary transporting conserved quantities (“charges”) between two systems initialized in thermal states. Three common formulae model the entropy produced. They respectively cast entropy as an extensive thermodynamic variable, as an information-theoretic uncertainty measure, and as a quantifier of irreversibility. Often, the charges are assumed to commute with each other (e.g., energy and particle number). Yet quantum charges can fail to commute.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Much like classical computing, quantum computers follow an abstraction model for their architecture. The performance of a quantum computer is dependent on the performance of each layer of this abstraction model, as well as the model itself. Due to its centrality in the quantum computing stack, the control system (consisting of hardware, firmware, and software) plays a strategically outsized role in the problem of quantum architecture.

Abstract: 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.