Quantum controlled-phase-flip gate between a flying optical photon and a Rydberg atomic ensemble

Abstract

Quantum controlled-phase-flip (CPF) gate between a flying photon qubit and a stationary atomic qubit could allow the linking of distant computational nodes in a quantum network. Here we present a scheme to realize quantum CPF gate between a flying optical photon and an atomic ensemble based on cavity input-output process and Rydberg blockade. When a flying single-photon pulse is reflected off the cavity containing a Rydberg atomic ensemble, the dark resonance and Rydberg blockade induce a conditional phase shift for the photon pulse, thus we can achieve the CPF gate between the photon and the atomic ensemble. Assisted by Rydberg blockade interaction, our scheme works in the N-atoms strong-coupling regime and significantly relaxes the requirement of strong coupling of single atom to photon in the optical cavity.

Precise single-qubit control of the reflection phase of a photon mediated by a strongly-coupled ancilla–cavity system

“…Proposals to use light to interlink quantum degrees of freedom of spatially separated nodes fall broadly in two categories. The first engages direct transmission of non-classical states of light [1][2][3][4][5][6][7][8], while the second heralds non-local quantum correlations by joint measurements on signals that are emitted from or have sequentially interacted with spatially separated quantum systems [9][10][11][12][13][14][15][16][17][18].…”

Strong photon blockade with intracavity electromagnetically induced transparency in a blockaded Rydberg ensemble

“…The atomic transition |g ↔ |e is resonantly coupled by the cavity mode with coupling strength g, while the control field with Rabi frequency Ω resonantly drives the transition |e ↔ |r 2 . Thus they form the three-level EIT configuration, with the interaction Hamiltonian [42] …”

“…The intracavity EIT provides an effective way to significantly enhance the cavity lifetime [37] and narrow the cavity linewidth [38][39][40]. Recently, it was shown that intracavity EIT could be used for the optical control of photon blockade and antiblockade effects with a single three-level atom trapped in a cavity [41] and the realization of quantum controlled-phase-flip gate between a fly- * Electronic address: gwlin@ecust.edu.cn † Electronic address: niuyp@ecust.edu.cn ‡ Electronic address: sqgong@ecust.edu.cn ing photon qubit and a stationary atomic qubit assisted by Rydberg blockade interaction [42]. In this paper, we consider the dynamics of intracavity EIT in an ensemble of strongly interacting Rydberg atoms and show that such intracavity EIT system could exhibit very strong photon blockade effect.…”

Decoherence in Excited Atoms by Low-Energy Scattering

“…One such technology is the quantum computer; trapped-ion systems have been implemented successfully to perform logical operations [1][2][3], making atomic systems a strong candidate for scalable quantum bits. Furthermore, the implementation of highly excited states (Rydberg atoms) has been proposed for quantum computing because of the length of their interaction and their long coherence times [3][4][5][6]. In order for atoms to be suitable for quantum technologies, it is necessary for them to have long coherence times, which is ultimately limited by their interaction with environmental particles [7].…”

“…Atoms 2016, 4,28 Author Contributions: The authors have contributed equally to the formulation of the theory and the calculations where performed by Diego A. Quiñones. Both authors have read and approved the final manuscript.…”