Seminar: Kristian Wold
It is a pleasure to invite you all to a MatMod / QHub / REGAL seminar by PhD candidate Kristian Wold from OsloMet – Oslo Metropolitan University.
Experimental Dissipative Quantum Chaos
Abstract: Classically chaotic systems are those where trajectories diverge exponentially as initial conditions are varied. However, it is not obvious how this can emerge from the more fundamental quantum mechanics, a linear theory. To see the connection, new mathematical tools for “Quantum Chaos” was developed, among them Random Matrix Theory (RMT) for studying quantum systems at the spectral level. Since its birth, RMT has been used to characterize signatures of chaos for closed quantum systems, both for theoretical models and physically realized experiments, showing good correspondence.
More recently, RMT is being expanded to also treat dissipative quantum systems, inventing tools for detecting chaotic and integrable (non-chaotic) signatures for quantum systems influenced by noise from an environment. However, experimental insights have lagged behind. We substantiate the field of Experimental Dissipative Quantum Chaos by utilizing noisy intermediate-scale quantum (NISQ) computers as a tunable testbed for detecting dissipative quantum chaos. To do this, we have invented a gradient-based quantum tomography protocol, letting us model NISQ circuits as quantum channels from measurement data.
We find that parameterized quantum circuits produce spectra whose support closely follow that of the Diluted Unitary model, a two-parameter stochastic model. Further, we device a type of circuit that lets us engineer artificial noise predicted by RMT to exhibit integrability. We find that we have sufficient experimental fidelity and sensitivity to detect said integrability when implemented on hardware, showing that it is a suitable testbed for similar investigations. Lastly, we find that, when you run the circuit for sufficient depth, there is a transition between integrability and chaos, showing that the intrinsic noise of the hardware has a chaotic nature.
Time and Location
Wednesday March 12th, 13:00 – 14:00
Ellen Gleditschs hus (P35), room PS439