Dispersive Photon Blockade in a Superconducting Circuit

TL;DR

This paper demonstrates dispersive photon blockade in a superconducting circuit, showing photon-photon interactions that block transmission, with a staircase pattern analogous to Coulomb blockade, highlighting a photonic nature of excitations.

Contribution

It introduces a dispersive photon blockade in a superconducting circuit where cavity-qubit excitations remain purely photonic, unlike previous hybridized systems.

Findings

Observation of a four-step staircase in transmitted power

Photon blockade analogous to Coulomb blockade in quantum dots

Photonic nature of cavity-qubit excitations maintained

Abstract

Mediated photon-photon interactions are realized in a superconducting coplanar waveguide cavity coupled to a superconducting charge qubit. These non-resonant interactions blockade the transmission of photons through the cavity. This so-called dispersive photon blockade is characterized by measuring the total transmitted power while varying the energy spectrum of the photons incident on the cavity. A staircase with four distinct steps is observed and can be understood in an analogy with electron transport and the Coulomb blockade in quantum dots. This work differs from previous efforts in that the cavity-qubit excitations retain a photonic nature rather than a hybridization of qubit and photon and provides the needed tolerance to disorder for future condensed matter experiments.