@pre-print{nokey,
title = {Circuit Complexity through phase transitions: consequences in quantum state preparation},
author = {Roca-Jerat, S.; Sancho-Lorente, T.; Román-Roche, J.; & Zueco, D. (2023). },
url = {https://quantumspain-project.es/wp-content/uploads/2023/01/Circuit-Complexity-through-phase-transitions_UNIZAR-1.pdf},
doi = { https://doi.org/10.48550/arXiv.2301.04671},
year = {2023},
date = {2023-01-11},
urldate = {2023-01-11},
abstract = {In this paper, we analyze the circuit complexity for preparing ground states of quantum manybody
systems. In particular, how this complexity grows as the ground state approaches a quantum
phase transition. We discuss dierent denitions of complexity, namely the one following the Fubini-
Study metric or the Nielsen complexity. We also explore dierent models: Ising, ZZXZ or Dicke.
In addition, dierent forms of state preparation are investigated: analytic or exact diagonalization
techniques, adiabatic algorithms (with and without shortcuts), and Quantum Variational Eigensolvers.
We nd that the divergence (or lack thereof) of the complexity near a phase transition depends on
the non-local character of the operations used to reach the ground state. For Fubini-Study based
complexity, we extract the universal properties and their critical exponents.
In practical algorithms, we nd that the complexity depends crucially on whether or not the system
passes close to a quantum critical point when preparing the state. While in the adiabatic case it is
dicult not to cross a critical point when the reference and target states are in dierent phases, for
VQE the algorithm can nd a way to avoid criticality.},
keywords = {adiabatic algorithms, algorithms, quantia, quantum, quantum computing},
pubstate = {published},
tppubtype = {pre-print}
}