Mike Thewalt, Simon Fraser University
Kristan Temme and Maris Ozols will be speaking at this Physics lunch seminar.
Approximation algorithms for classical constraint satisfaction problems are one of the main research areas in theoretical computer science. A natural generalization of constraint satisfaction problems to the quantum setting is the local Hamiltonian problem, which is of significant interest to both complexity theorists and to physicists studying properties of physical systems alike. In this talk, we define a natural approximation version of the local Hamiltonian problem and initiate its study. We present two main results.
Mike Geller, University of Georgia
Seth Lloyd, Massachusetts Institute of Technology
Ever since Einstein, physicists have argued about whether time travel is consistent with the laws of physics, and, if so, how it might be accomplished. This talk presents a new theory of time travel based on quantum teleportation. Unlike previous theories, the theory can be tested experimentally. I report on an experimental realization of the 'grandfather paradox': we send a photon a few billionths of a second backwards in time and have it try to 'kill' its previous self.
Falk Unger, University of California, Berkeley
Todd Pittman, University of Maryland, Baltimore County
Britton Plourde, Syracuse University
Nathan Wiebe, University of Calgary
We introduce an efficient quantum algorithm for simulating time-dependent Hamiltonian quantum dynamics on a quantum computer and accounts fully for all computational resources, especially the per-qubit oracle query cost, which has been previously regarded as constant cost per query regardless of the number of qubits accessed.
Adrian Lupascu, Institute for Quantum Computing
Quantum superconducting circuits are nanostructured superconducting electrical networks with Josephson junctions. At low temperatures, their quantum dynamics is properly described by using a few degrees of freedom with a collective character. The parameters in the Hamiltonian depend on the dimensions and topology of the circuit; superconducting quantum circuits therefore behave as artificial atoms.