New JQI Fellow Brings Laser Focus to Quantum Research into Chemistry
Lasers are often misunderstood, according to chemical physicist and JQI Fellow Yu Liu. “People usually think of lasers as heating things up, but if you use the right frequency of lasers and target the right type of atoms, you can actually take energy away,” Liu says. This technique—laser cooling—is his specialty.
Developing a strong driving toolkit for Floquet systems with superconducting qubits
Dissertation Committee Chair: Alicia Kollár
Committee:
Ben Palmer
Steven Rolston
Nathan Schine
Ron Walsworth (Dean’s Rep)
Experimental observation of symmetry-protected signatures of N-body interactions
Characterizing higher-order interactions in quantum processes with unknown Hamiltonians presents a significant challenge. This challenge arises, in part, because two-body interactions can lead to an arbitrary evolution, and two-local gates are considered universal in quantum computing. However, recent research has demonstrated that when the unknown Hamiltonian follows a U(1) symmetry, like charge or number conservation, N-body interactions display a distinct and symmetry-protected feature called the N-body phase.
Twisted Light Gives Electrons a Spinning Kick
Scientists seeking better methods for controlling the quantum interactions between light and matter demonstrated a novel way to use light to give electrons a spinning kick. In the journal Nature Photonics, they reported the results of an experiment, showing that a light beam can reliably transfer orbital angular momentum to itinerant electrons in graphene.
When less is more; modelling and simulating new approaches in quantum sensing
Quantum sensing extends the vast benefits of a quantum advantage to traditional metrology. A common method of quantum sensing utilizes coherent, crystal defects in semi-conductors (such as nitrogen vacancy centers in diamond) to perform high-precision measurements on a variety of length scales. Such measurements might span from vectorized magnetometry of macroscopic computer chips to nanoscale strain or temperature mapping in a target matrial. In exploring new regimes for quantum sensing, we need to model and assess their viability through theoretical or simula
Repurposing Qubit Tech to Explore Exotic Superconductivity
The established knowledge and technical infrastructure from decades of quantum research are allowing researchers to harness quantum technologies in unexpected, innovative ways and creating new research opportunities. In a paper published in the journal Nature Physics, a collaboration between theorists at JQI and experimentalists at Harvard University presented a technique that repurposes the technology of superconducting circuits to study samples with exotic forms of superconductivity. The collaboration demonstrated that by building samples of interest into a superconducting circuit they could spy on exotic superconducting behaviors that have eluded existing measurement techniques.
Measurement-induced entanglement and complexity in random constant-depth 2D quantum circuits
We analyse the entanglement structure of states generated by random constant-depth two-dimensional quantum circuits, followed by projective measurements of a subset of sites. By deriving a rigorous lower bound on the average entanglement entropy of such post-measurement states, we prove that macroscopic long-ranged entanglement is generated above some constant critical depth in several natural classes of circuit architectures, which include brickwork circuits and random holographic tensor networks.