## Combinatorial Optimization Problems, Spin Glasses and Quantum Entanglement

**Speaker:**Bernardo Zubillaga

**When:**December 4, 2015 (Fri), 01:00PM to 02:00PM (add to my calendar)

**Location:**SCI 328

*This event is part of the Preliminary Oral Exam. *

Examining Committee: Claudio Chamon, William Klein, So-Young Pi, Michael El-Batanouny

Abstract:

Recent developments in quantum computing have led to the physical implementation of quantum annealing with the purpose of solving combinatorial optimization problems. The behavior of such devices as the D-Wave machine raises questions on the role of quantum entanglement in quantum annealing protocols. We address these questions by determining the scaling of the entanglement entropy as a measure of the computational complexity of the problem of finding the ground state of an Ising spin glass. This is done for 2 protocols: adiabatic quantum computing and a non-unitary projection method in imaginary time. These protocols are simulated with Matrix Product States, limiting the amount of entanglement stored by the state of the system, allowing to study the effect of entanglement control on the success rates of these quantum protocols.