CMTC Seminar

We investigate 2-dimensional periodic superstructures consisting of 1-dimensional conducting segments. Such structures naturally appear in twisted transition metal dichalcogenides, some charge-density-wave materials, and a marginally twisted bilayer graphene, in which intriguing non-Fermi liquid transports have been experimentally observed. We model such a system as a network of Tomonaga-Luttinger Liquids, and theoretically derive a variety of non-Fermi liquid behaviors, based on a Renormalization-Group analysis of the junctions of Tomonaga-Luttinger Liquids.

Abstract: New experimental methods such as nitrogen vacancy center magnetometry allow for the imaging of local transport phenomena well below the micron length scale. I will describe how these methods might be used to experimentally reveal quantum critical dynamics which is invisible in conventional bulk transport measurements. Using a holographic system as a toy model, I will describe what happens as current is pushed through a geometric constriction in both hydrodynamic and quantum critical transport regimes, both in charge neutral and non-zero density limits.

Abstract: Ultracold atomic gases have proven to provide valuable platforms to simulate quantum systems arising in disparate areas of physics. Polarons are well-studied quasiparticles in solid-state systems that describe an electron dressed by lattice distortions. The so-called Frohlich model is the typical starting point for theoretically describing such systems. More recently, polarons arising in Bose-Einstein condensates have been the focus of much attention, both theoretical and experimental.

Abstract: Recent demonstration of the first beyond classical quantum computation with a programmable superconducting quantum processor [1] opens the path to discovery of new quantum physics phenomena using these hardware systems. Gate model quantum computers used in [1] realize complex multi-qubit evolution in terms of discrete gates, elementary one and two qubit unitary operations, practically realized by a local time-dependent control Hamiltonian. In this talk we overview the recent many-body physics experiments implemented on these processors.

Electron spins in silicon quantum dots are attractive quantum bits (qubits) due to their long coherence times and the promise of rapid scaling using semiconductor fabrication techniques. While nearest neighbor exchange coupling has been recently demonstrated in Si, the interaction of spins via microwave frequency photons could enable long distance spin-spin coupling and “all-to-all” qubit connectivity. I will describe experiments where we couple a single spin in silicon to a single microwave frequency photon.