Flux-Tunable Hybridization in a Double Quantum Dot Interferometer

Kavli Affiliate: Srijit Goswami

| First 5 Authors: [#item_custom_name[1]], [#item_custom_name[2]], [#item_custom_name[3]], [#item_custom_name[4]], [#item_custom_name[5]]

| Summary:

A single fermion shared between two states threaded by a magnetic flux is the
simplest possible quantum system in which interference is predicted to occur.
We demonstrate tuning of the tunnel coupling between two such fermionic levels
with flux, implemented in a phase-coherent loop comprising two quantum dots.
Using radio-frequency reflectometry of the dots’ gate electrodes, we probe the
device tuned into an open loop without tunnel barriers. There, we observe
signal oscillations in magnetic field consistent with the Aharonov-Bohm effect.
Tuning the ring into a loop-shaped double quantum dot, we extract the inter-dot
tunnel coupling as a function of flux, which exhibits oscillations with the
same periodicity. In different tunnel coupling regimes we benchmark the
contrast of these oscillations, and find that their amplitude varies depending
on the levels involved, while tunneling is generically not suppressed at
oscillation minima. These results establish the feasibility and limitations of
conducting parity readout of hybrid qubits with tunnel couplings tuned by flux.

| Search Query: [#feed_custom_title]

Read More