TY  - JOUR
AU  - Bode, Tim
AU  - Kajan, Michael
AU  - Meirinhos, Francisco
AU  - Kroha, Johann
TI  - Non-Markovian dynamics of open quantum systems via auxiliary particles with exact operator constraint
JO  - Physical review research
VL  - 6
IS  - 1
SN  - 2643-1564
CY  - College Park, MD
PB  - APS
M1  - FZJ-2024-01810
SP  - 013220
PY  - 2024
AB  - We introduce an auxiliary-particle field theory to treat the non-Markovian dynamics of driven-dissipative quantum systems of the Jaynes-Cummings type. It assigns an individual quantum field to each reservoir state and provides an analytic, faithful representation of the coupled system-bath dynamics. We apply the method to a driven-dissipative photon Bose-Einstein condensate (BEC) coupled to a reservoir of dye molecules with electronic and vibronic excitations. The complete phase diagram of this system exhibits a hidden, non-Hermitian phase transition separating temporally oscillating from biexponentially decaying photon density correlations within the BEC. On one hand, this provides a qualitative distinction of the thermal photon BEC from a laser. On the other hand, it shows that one may continuously tune from the BEC to the lasing phase by circumventing a critical point. This auxiliary-particle method is generally applicable to the dynamics of open, non-Markovian quantum systems.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001187633700003
DO  - DOI:10.1103/PhysRevResearch.6.013220
UR  - https://juser.fz-juelich.de/record/1023797
ER  -