JQI

Abstract: In this talk, I will present a construction of symmetric informationally complete POVMs (SIC-POVMs), a special class of quantum measurements whose existence in all dimensions was conjectured by Zauner in 1999. Equivalently, these are maximal sets of d^2 equiangular lines in ℂ^d. Our approach introduces an explicit mathematical object, the ghost SIC, built from number-theoretic properties of a special modular function, and we show that it is Galois conjugateto an actual SIC.

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.

Abstract: Unlike the traditional study of algorithms which attempts to solve a certain task using minimal space and time resources, I will discuss data structures to solve certain algorithmic tasks after an initial pre-processing phase. The interest here is to study the tradeoffs between the resources such as the space and time required to perform the algorithmic task when asked a query; and the resources in the pre-processing phase such as the time required to prepare the data structure or its size.

Abstract: 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.

Abstract: Permutation-invariant quantum error correction codes that are invariant under any permutation of the underlying particles. These codes could have potential applications in quantum sensors and quantum memories. Here I will review the field of permutation-invariant codes, from code constructions to applications.

*We strongly encourage attendees to use their full name (and if possible, their UMD credentials) to join the zoom session.*

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.