Resonant transverse driving of a two-level system as viewed in the rotating frame couples two degenerate states at the Rabi frequency, an amazing equivalence that emerges in quantum mechanics. While spectacularly successful at controlling natural and artificial quantum systems, certain limitations may arise (e.g., the achievable gate speed) due …

I’ve been building Powerpoint-based quantum computers with electron spins in silicon for 19 years. Unfortunately, real-life-based quantum dot quantum computers are harder to implement. Fabrication, control, and materials challenges abound. The way to accelerate discovery is to make and measure more qubits. Here I discuss separating the qubit realization …

The pursuit of superconducting-based quantum computers has advanced the fabrication of and experimentation with custom lattices of qubits and resonators. Here, we describe a roadmap to use present experimental capabilities to simulate an interacting many-body system of bosons and measure quantities that are exponentially difficult to calculate numerically. We focus …

Existing schemes for semiconductor spin qubit readout involve either spin-to-charge conversion or electric dipole coupling to a superconducting resonator. The former requires destructive readout while the latter suffers from enhanced qubit dephasing, limiting the potential performance of quantum measurement: an open challenge in semiconductor quantum computing. Here we propose a …

We propose a non-destructive means of characterizing a semiconductor wafer via measuring the parameters of an induced quantum dot on the material system of interest with a separate probe chip that can also house the measurement circuitry. We show that a single wire can create the dot, determine if an …

On the route towards a useful quantum computer, we must not ignore the materials challenges facing us nor the opportunities that materials science may provide for disruptive new qubits.

Graphene qubit motivates materials science (nature.com)

We theoretically model the spin-orbit interaction in silicon quantum dot devices, relevant for quantum computation and spintronics. Our model is based on a modified effective mass approach which properly accounts for spin-valley boundary conditions, derived from the interface symmetry, and should have applicability for other heterostructures. We show how the …

We propose a non-destructive means of characterizing quantum dot parameters across a semiconductor wafer by inducing a quantum dot on the material system of interest with a separate probe chip that can also house the measurement circuitry. We show that a single wire can create the dot, determine if an …

We present a theory for understanding the exchange interaction between electron spins in neighboring quantum dots, either by changing the detuning of the two quantum dots or independently tuning the tunneling barrier between quantum dots. The Hubbard model and a more realistic confining-potential model are used to investigate how the …

There are still new physics to discover in circuit-QED-like systems. We investigate coupling an encoded spin qubit to a superconductor resonator via qubit energy level curvature versus gate voltage [1].This approach enables quantum non-demolition readout with strength of tens to hundred MHz all while the qubit stays …