Deterministic generation of a four-component optical cat state

Abstract

The four-component cat state represents a particularly useful quantum state for realizing faulttolerant continuous variable quantum computing. While such encoding has been experimentally generated and employed in the microwave regime, the states have not yet been produced in the optical regime. Here we propose a simple linear optical circuit combined with photon counters for the generation of such optical four-component cat states. This work might pave the way for the first experimental generation of fault-tolerant optical continuous variable quantum codes.

Wave-function engineering via conditional quantum teleportation with non-Gaussian entanglement resource

“…In addition to the usual cat state, there is also an important class of state called four-component cat state [22,49,50]. This type of state is a superposition of four coherent states, i.e.…”

“…In addition, non-Gaussian states also have many other applications. For example, a superposition of coherent states-commonly known as a Schrödinger cat state-have applications in quantum computation [15][16][17][18], quantum communication [19,20], and quantum error correction [21][22][23]. Another non-Gaussian state called Gottesman-Kitaev-Preskill (GKP) qubit is currently the most promising logical qubit for fault-tolerant CV quantum computation [14,[24][25][26][27][28][29].…”

“…Then, we can find a setup that consists of squeezed light sources, linear optics, and photon number detectors that herald |ψ target when particular results are detected by the photon number detectors. Based on this idea, generations of various non-Gaussian states have been explored [18,22,[29][30][31][32][33][34][35][36][37][38][39][40][41]. In this approach, however, the generation system is highly dependent on the target states and the generation systems tend to become more complex when the maximum photon number increases.…”

Sub-Planck structures: Analogies between the Heisenberg-Weyl and SU(2) groups

“…As prototypical states that show such sub-Planck features, he built the so-called compass states (one coherent state, so to speak, at the north, south, east and west corners), superposition of four distant coherent states, which can also be understood as superpositions of two cat states. By now, there are multiple theoretical proposals for the controlled generation of these states [27][28][29][30][31][32], apart from actual experimental implementations [33][34][35][36][37], and their properties and effects in different contexts have been well explored [38][39][40][41][42][43][44][45][46][47][48][49][50][51].…”

Amplification of optical Schrödinger cat states with implementation protocol based on frequency comb

“…Odd(Even) cats are featured with odd(even) photon number distribution. Different from the mixture states, superposition states reveal the interference between superposed components, which play an important role in the verification of quantum nonlocality [2], quantum communication [3][4][5], continuous-variable quantum computation [6][7][8][9][10] and quantum metrology [11,12]. One-photon subtracted squeezed vacuum state is a standard method to generate Schrödinger cat states with small size, which is defined as Schrödinger kitten states [1].…”