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Universal Witnesses of Vanishing Energy Gap by Szymański, Konrad; Życzkowski, Karol is a scholarly article available to read on EtoBox.

What is Universal Witnesses of Vanishing Energy Gap about?

Energy gap, the difference between the energy of the ground state of a given Hamiltonian and the energy of its first excited state, is a parameter of a critical importance in analysis of phase transitions and adiabatic quantum computation. We present a concrete technique to determine the upper bound for the energy gap of a Hamiltonian $H_0$ based on properties of the set of expectation values of $H_0$ and an additional auxiliary Hamiltonian $V$. This formalism can be applied to obtain an effective criterion of gaplessness, which we illustrate with a concrete example of the XY model -- a physical system with vanishing energy gap.

Author

Szymański, Konrad; Życzkowski, Karol

Published

2021

Language

EN