Two-mode squeezed states as Schrödinger-cat-like states

Enky Oudot, Pavel Sekatski, Florian Fröwis and Nicolas Sangouard

Quantum Optics Theory Group, University of Basel, Switzerland

In recent years, there has been an increased interest in the generation of superposition of coherent states with opposite phases, the so-called photonic Schrödinger-cat states. These experiments are very challenging and so far, cats involving small photon numbers only have been implemented. Here we explore the macroscopic character of squeezed states by developing a framework where one can compare the size of a squeezed state with the size of a Schrödinger cat state. We show how these criteria can be extended to continuous variable entangled states. We apply it to various squeezed states, argue that two-mode squeezed vacuum states belong to a class of general Schrodinger-cat states and compare the size of states obtained in several experiments. Our results not only promote two-mode squeezed states for exploring quantum effects at the macroscopic level but also provide direct measures to evaluate their usefulness for quantum metrology.