Will quantum interior point methods be practical? An end-to-end resource analysis for portfolio optimization incorporating improvements to state preparation
Abstract: Despite much work on quantum algorithms, there are few examples of practically relevant computational tasks that are known to admit substantial quantum speedups for practical instance sizes after all hidden costs and caveats are considered. Portfolio optimization (PO) is a practically important problem that can be solved via Quantum Interior Point Methods (QIPMs) via a standard mapping to a Second-Order Cone Programs (SOCP). Preliminary numerical evidence in prior literature was consistent with an asymptotic quantum speedup. But will this solution be practical?
Another Round of Breaking and Making Quantum Money: How to Not Build It from Lattices, and More
Abstract: Public verification of quantum money has been one of the central objects in quantum cryptography ever since Wiesner's pioneering idea of using quantum mechanics to construct banknotes against counterfeiting. So far, we do not know any publicly-verifiable quantum money scheme that is provably secure from standard assumptions.
In this talk, we provide both negative and positive results for publicly verifiable quantum money.
Phonon-Polaritons via the Cavity Born-Oppenheimer Approximation
Abstract: Strong light-matter coupling in optical cavities can alter the dynamics of molecular and material systems resulting in polaritonic excitation spectra and modified reaction pathways. For strongly coupled photon modes close in energy to nuclear vibrations the Cavity Born Oppenheimer Approximation (CBOA) in the context of quantum-electrodynamical density functional theory (QEDFT) has been demonstrated to be an appropriate description of the coupled light-matter system.
Pauli stabilizer models of twisted quantum doubles
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.
Excitonic Mott insulator in a Bose-Fermi-Hubbard system of moiré WS2-WSe2 heterobilayer
Abstract: Understanding the Hubbard model is crucial for investigating various quantum many-body states and its fermionic and bosonic versions have been largely realized separately. Recently, transition metal dichalcogenides heterobilayers have emerged as a promising platform for simulating the rich physics of the Hubbard model. In this work, we explore the interplay between fermionic and bosonic populations, using a WS2/WSe2 heterobilayer device that hosts this hybrid particle density.
Exciton Condensates Through the Years
Abstract: Excitons are composite Bosons formed by pairing electrons and holes in a crystal.The idea that excitons might Bose condense dates to the 1960’s but has often been surrounded by controversy. My talk will focus on the important lessons learned
about exciton condensates from work on two-dimensional electron systems in the
quantum Hall regime, starting around twenty years ago, and on new opportunities
Quantum algorithm for simulating coupled classical oscillators
Abstract: I will describe a recent quantum algorithm (arXiv:2303.13012) for simulating the classical dynamics of 2^n coupled oscillators (e.g., 2^n masses coupled by springs). The algorithm is based on a mapping between the Schr\"odinger equation and Newton's equations for harmonic potentials such that the amplitudes of the evolved quantum state encode the momenta and displacements of the classical oscillators.
Stabilizer codes: the continuous, the infinite, and the exotic
Abstract: Traditional stabilizer codes operate over prime power local-dimensions. For instance, the 5-qubit code and 9-qubit code operate over local-dimension 2. In this presentation we discuss extending the stabilizer formalism using the local-dimension-invariant framework to import stabilizer codes from these standard local-dimensions to other cases.
Quantum simulation of entangled matter with continuous symmetry breaking in a trapped-ion quantum computer
One-dimensional systems exhibiting a continuous symmetry can host quantum phases of matter with true long-range order only in the presence of sufficiently long-range interactions. In most physical systems, however, the interactions are short-ranged, hindering the emergence of such phases in one dimension. Trapped-ion quantum computers provide a pristine one-dimensional spin system, featuring high isolation from the environment, high-fidelity measurement and preparation of individual spins, and fully connected spin-spin interactions.
Learning properties of interacting fermionic systems with limited hardware
Abstract: Interacting fermionic systems can model real world physical phenomenon directly. Many people are working on finding efficient and practical ways to determine properties of these quantum simulators. Specifically, estimating correlation functions, that reveal important properties such as coulomb-coulomb interaction strength and entanglement spreading, is a crucial goal. The well know classical shadows formalism allows one to find linear properties of a quantum state by reusing outcomes from simple basis measurements.