Środowiskowe Seminarium z Informacji i Technologii Kwantowych
sala 1.03, ul. Pasteura 5
2024-01-25 (11:15) 
Jing Yang (Royal Institute of Technology and Stockholm University)
Precision Limits in Many-body Quantum Sensing [ONLINE!]
ONLINE SEMINAR: Meeting ID: 928 9413 0767, Passcode: R6Vx6E
Many-body interactions can introduce entanglement between particles and hence are valuable resources for quantum information processing. In quantum metrology, the precision can be further boosted by adding many-body interactions. I will discuss an optimal control theory for controlling many-body interaction with restricted operations, in the context of quantum sensing. We show that in a spin chain model the Heisenberg scaling can be still achieved even though the control operations are restricted, given an initial GHZ-like state can be prepared. When the GHZ state cannot be efficiently prepared in experiments, one may consider many-body sensing with separable initial states. We find that using separable initial states cannot beat the shot noise limit in locally interacting systems, unless long-range non-local interactions are utilized. These findings identify two important ingredients in many-body sensing: initial entanglement and long-range interactions. I will conclude briefly commenting the local optimal measurements that can be performed to extract the many-body precision limits.
Many-body interactions can introduce entanglement between particles and hence are valuable resources for quantum information processing. In quantum metrology, the precision can be further boosted by adding many-body interactions. I will discuss an optimal control theory for controlling many-body interaction with restricted operations, in the context of quantum sensing. We show that in a spin chain model the Heisenberg scaling can be still achieved even though the control operations are restricted, given an initial GHZ-like state can be prepared. When the GHZ state cannot be efficiently prepared in experiments, one may consider many-body sensing with separable initial states. We find that using separable initial states cannot beat the shot noise limit in locally interacting systems, unless long-range non-local interactions are utilized. These findings identify two important ingredients in many-body sensing: initial entanglement and long-range interactions. I will conclude briefly commenting the local optimal measurements that can be performed to extract the many-body precision limits.