Variational preparation of finite-temperature states on a quantum computer
Abstract
The preparation of thermal equilibrium states is important for the simulation of condensed matter and cosmology systems using a quantum computer. We present a method to prepare such mixed states with unitary operators and demonstrate this technique experimentally using a gate-based quantum processor. Our method targets the generation of thermofield double states using a hybrid quantum-classical variational approach motivated by quantum-approximate optimization algorithms, without prior calculation of optimal variational parameters by numerical simulation. The fidelity of generated states to the thermal-equilibrium state smoothly varies from 99 to 75% between infinite and near-zero simulated temperature, in quantitative agreement with numerical simulations of the noisy quantum processor with error parameters drawn from experiment.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 20, 2021
- Source ID
- 10.1038/s41534-021-00468-1
Entities
People
- A. Y. Matsuura
- Adriaan Rol
- B. A. Klaver
- Bruno Andò
- Christos Zachariadis
- Leonardo Dicarlo
- M. Beekman
- M. S. Moreira
- N. Haider
- Nandini Muthusubramanian
- R. Sagastizabal
- S. Johri
- Shavindra P Premaratne
- Viacheslav Ostroukh
- Victor Negîrneac
- Xun Zou
Organizations
- European Research Council
- Intel Corporation
- Intelligence Advanced Research Projects Activity