2020 Physics/Theoretical Colloquium Thursday, March 12th , 2020 3:45 – 4:45 p.m. Rosen Auditorium (TA-53, Bldg. 001) Refreshments at 3:15pm Speaker: Prof. Lincoln Carr Department of Physics, Colorado School of Mines “Reservoir engineering and many-body decoherence in the quantum Ising model” Abstract: Abstract: We present quantitative predictions for quantum simulator experiments on Ising models from trapped ions to Rydberg chains and show how the thermalization, and thus decoherence times, can be controlled by considering common, independent, and end-cap couplings to the bath. We find (i) independent baths enable more rapid thermalization in comparison to a common one; (ii) the thermalization timescale depends strongly on the position in the Ising phase diagram; (iii) for a common bath larger system sizes show a significant slowdown in the thermalization process; and (iv) finite-size scaling indicates a subradiance effect slowing thermalization rates toward the infinite spin chain limit. We find it is necessary to treat the full multichannel Lindblad master equation rather than the commonly used single-channel local Lindblad approximation to make accurate predictions on a classical computer. This method reduces the number of qubits one can practically classical simulate by at least a factor of 4, in turn showing a quantum advantage for such thermalization problems at a factor of 4 smaller qubit number for open quantum systems as opposed to closed ones. Thus, our results encourage open quantum system exploration in noisy intermediate-scale quantum technologies. Reference: Daniel Jaschke, Lincoln D. Carr, and Ines de Vega, "Thermalization in the quantum Ising model—approximations, limits, and beyond," Quantum Science and Technology 4, 034002 (2019), https://doi.org/10.1088/2058-9565/ab1a71 https://physics.mines.edu/project/carr-lincoln/ If you are interested in meeting with the speaker, please contact his host: Kurkcuoglu, Doga Murat