Modified Quantum Imaginary Time Evolution Algorithm and Potential Applications in Fusion Energy Science
ORAL
Abstract
There is increasing interest in quantum algorithms that are based on the imaginary-time evolution (ITE), a successful
classical numerical approach to obtain ground states. However, most of the proposed quantum algorithms that are based
on ITE require heavy post-processing computational steps on a classical computer, such as solving linear equations. In
this talk we introduce an alternative implementation of ITE on gate-based quantum computers -- modified quantum imaginary
time evolution (MQITE) algorithm [1]. MQITE allows the propagated state to be efficiently expressed
in terms of a limited number of orthogonal basis states at every step of the evolution. The small number of basis states
means the quantum circuit depth can be bounded to only $mathcal{O}(poly(n))$, given $n$ qubits. The algorithm is not
restricted to local Hamiltonian, which renders it useful for studying highly nonlocal systems, such as the occupation-representation
nuclear shell model. MQITE as an algorithm to simulate non-unitary time evolution, such as plasma dynamics, is discussed as well.
The algorithm is illustrated through numerical implementation on IBM quantum simulator.
[1] P. Jouzdani, C. W. Johnson, E. R. Mucciolo, and I. Stetcu, Phys. Rev. A 106, 062435 (2022)
classical numerical approach to obtain ground states. However, most of the proposed quantum algorithms that are based
on ITE require heavy post-processing computational steps on a classical computer, such as solving linear equations. In
this talk we introduce an alternative implementation of ITE on gate-based quantum computers -- modified quantum imaginary
time evolution (MQITE) algorithm [1]. MQITE allows the propagated state to be efficiently expressed
in terms of a limited number of orthogonal basis states at every step of the evolution. The small number of basis states
means the quantum circuit depth can be bounded to only $mathcal{O}(poly(n))$, given $n$ qubits. The algorithm is not
restricted to local Hamiltonian, which renders it useful for studying highly nonlocal systems, such as the occupation-representation
nuclear shell model. MQITE as an algorithm to simulate non-unitary time evolution, such as plasma dynamics, is discussed as well.
The algorithm is illustrated through numerical implementation on IBM quantum simulator.
[1] P. Jouzdani, C. W. Johnson, E. R. Mucciolo, and I. Stetcu, Phys. Rev. A 106, 062435 (2022)
*This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award Number(s) DE-SC0019465; Office of Basic Energy Sciences under Award Number(s) DE-SC0019275; Office of Fusion Energy Sciences, under Award Number(s) DE-SC0020249; and the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory, under Award Number(s) 89233218CNA000001 as well as partial support by the Advanced Simulation and Computing (ASC) Program.
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Publication: [1] P. Jouzdani, C. W. Johnson, E. R. Mucciolo, and I. Stetcu, Phys. Rev. A 106, 062435 (2022)
Presenters
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Pejman Jouzdani
- General Atomics