Probing and controlling many-body dynamics on quantum simulation devices

• Applicant: Dr. Anne Matthies
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Theoretical Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 549314503

Quantum many-body systems exhibit numerous novel phases and emergent collective phenomena holding answers to deep questions like the nature of phase transitions and the origin of quantum coherence. With implications beyond conventional condensed matter physics, they are a natural platform for studying quantum information processing, like quantum simulation, sensing, and metrology. Understanding the dynamics of entanglement and quantum correlation in many-body systems is fundamental for the behavior of a quantum system and crucial for designing new quantum algorithms and quantum computation architectures. One of the most promising near-term applications of quantum computing is the simulation of many-body dynamics, which becomes quickly inaccessible for classical computers with increasing system size and time. Indeed, the main focus of this theory proposal is to explore many-body dynamics on currently available quantum simulation devices. Specifically, the project centers around Rydberg tweezer arrays and hybrid NV-P1 platforms. Recently, Rydberg atom arrays, operated at very low temperatures, have made significant progress towards becoming a programmable quantum computer, with up to 48 logical qubits. In contrast, nitrogen-vacancy (NV) centers and substitutional Nitrogen defects (P1) in diamond can be addressed at room temperature. Hybrid NV-P1 platforms naturally form a dilute dipolar spin system with a low filling fraction of the two defects within the diamond lattice. Both of these platforms have applications in the fields of quantum computing, simulation, and sensing. This project aims to control and probe many-body dynamics with only a few accessible programmable local degrees of freedom leveraging the two platforms. Both cooling towards the ground state and creating highly excited states with an effective negative temperature will be explored. On hybrid NV-P1 platforms, efficient local cooling is highly relevant, for example, to investigate glassy physics that might be exhibited by dilute dipolar spin systems. Furthermore, we will investigate the radiation profile arising due to the instability of negative temperature states and the possibility of observing superradiance in Rydberg tweezer arrays. Reaching negative temperature has a number of interesting applications, such as exploring new phases of the inverted Hamiltonian, energy storage devices, and, of interest for high energy physics, negative pressure in quantum simulation. Finally, we will draw on the connection between many-body dynamics and quantum thermodynamics and investigate how negative temperature states can be leveraged to construct useful quantum thermodynamic devices like quantum batteries.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professor Norman Yao, Ph.D.