Both discrete and continuous signals are used to carry classical information. Analogously, discrete and continuous systems can be used to encode quantum information. Most quantum computation schemes propose enconding qubits using two level systems, such a two-level atom or an electron spin. Others exploit the use of a infinite-dimensional system, such as a harmonic oscillator. In Gottesman et al.  a qubit is encoded in the continuous position and momentum degrees of freedom of an oscillator (Gottesman - Kitaev - Preskill or GKP qubit states). One advantage of this proposed scheme is that it can be performed using relatively simple linear optical devices, squeezing, and homodyne detection. However, the inicial GKP states are extremely difficult to prepare. Here we propose the generation of an approximate GKP state by using superpositions of optical coherent states (sometimes called Schrodinger cat states ), squeezing, linear optical devices, and homodyne detection.
Citation: Optics Letters
Pub Type: Journals
linear optical quantum computer, Schrodinger cat state