TY  - JOUR
AU  - Bode, Tim
AU  - Wilhelm, Frank K.
TI  - Adiabatic bottlenecks in quantum annealing and nonequilibrium dynamics of paramagnons
JO  - Physical review / A
VL  - 110
IS  - 1
SN  - 2469-9926
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2024-05350
SP  - 012611
PY  - 2024
AB  - The correspondence between long-range interacting quantum spin glasses and combinatorial optimization problems underpins the physical motivation for adiabatic quantum computing. On one hand, in disordered (quantum) spin systems, the focus is on exact methods such as the replica trick that allow the calculation of system quantities in the limit of infinite system and ensemble size. On the other hand, when solving a given instance of an optimization problem, disorder-averaged quantities are of no relevance, as one is solely interested in instance-specific, finite-size properties, in particular the optimal solution. Here, we apply the nonequilibrium Green's function formalism to the spin coherent-state path integral to obtain the statistical fluctuations and the collective-excitation spectrum along the annealing path. For the example of the quantum Sherrington-Kirkpatrick spin glass, by comparing to extensive numerically exact results, we show that this method provides access to the instance-specific bottlenecks of the annealing protocol.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001267517200009
DO  - DOI:10.1103/PhysRevA.110.012611
UR  - https://juser.fz-juelich.de/record/1030617
ER  -