Events at Physics |
I will discuss a collaboration with the Kuzmin group, in which we utilized single-photon splitting to observe the Schmid-Bulgadaev quantum phase transition, whose lack of clear evidence has sparked a recent debate. The experimental system realizes the boundary sine-Gordon model, which is known to be integrable and is characterized by purely elastic scattering of elementary excitations, that seems at odds with photon splitting. I will show that a nonlinear relation between these excitations and the photons not only allows for inelastic decay of the latter, but also that integrability provides powerful analytical tools yielding exact results for the total inelastic decay rate and the spectrum of the resulting photons. Our results shed light on the Schmid-Bulgadaev transition, and compare nicely with experimental measurements.