The solution of linear systems of equations is the basis of many other quantum algorithms, and recent results provided an algorithm with optimal scaling in both the condition number and the allowable error \cite{CostaAnYuvalEtAl2022}. That work was based on the discrete adiabatic theorem, and worked out an explicit constant factor for an upper bound on the complexity. Here we show via numerical testing on random matrices that the constant factor is in practice about 1,200 times smaller than the upper bound found numerically in the previous results. That means that this approach is far more efficient than might naively be expected from the upper bound. In particular, it is about an order of magnitude more efficient than using a randomised approach from \cite{jennings2023efficient} that claimed to be more efficient.
more »
« less
The central role of entropy in adiabatic ensembles and its application to phase transitions in the grand-isobaric adiabatic ensemble
- Award ID(s):
- 1955403
- PAR ID:
- 10215817
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 153
- Issue:
- 9
- ISSN:
- 0021-9606
- Page Range / eLocation ID:
- 094114
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Adiabatic subtraction is a popular method of renormalization of observables in quantum field theories on a curved spacetime. When applied to the computation of the power spectra of light ( m ≪ H ) fields on de Sitter space with flat Friedmann-Lemaître-Robertson-Walker slices, the standard prescriptions of adiabatic subtraction, traceable back to [1,2], lead to results that are significantly different from the standard expectations not only in the ultraviolet ( k ≫ aH ) but also at intermediate ( m ≪ k / a ≲ H ) wavelengths. In this paper we review those results and we contrast them with the power spectra obtained using an alternative prescription for adiabatic subtraction applied to quantum field theoretical systems by Dabrowski and Dunne [3,4]. This prescription eliminates the intermediate-wavelength effects of renormalization that are found when using the standard one.more » « less
An official website of the United States government

