In spin-encoded quantum information, a spin of magnitude s gives access to a (2s+1)-dimensional qudit. (In particular, s=1/2 yields a qubit). Quantum optics writ large as the quantum processing of boson fields has provided convenient experimental ways to generate effective, or "synthetic," spins by way of mathematical equivalences such as the Holstein-Primakoff transformation, which maps 1 boson field to 1 large, "linearized" spin, and the Schwinger transformation, which maps 2 boson fields to 1 spin. The latter is of particular interest as it also maps bijectively with two-mode Fock states, which have non-Gaussian Wigner functions and therefore enable, in principle, universal, fast-tolerant photonic quantum computing. The recent coming of age of high-efficiency photon-number-resolved detectors provided the missing experimental resource to work with Schwinger spins. In this talk, I will describe progress towards experimentally violating Mermin's inequality (the s>1/2 version of the Bell inequality) using superconducting transition edge sensors in our quantum optics laboratory.
|