Towards Multiphoton State Generation in Delay Loops

Stefano Cavalieri, Marzia Materazzi, R. Eramo +2 more

M.E. Perel'man, V. G. Arutyunyan

Shengwang Du

E. Megidish, H. S. Eisenberg

The generation of multiphoton entanglement conventionally requires large amounts of resources. We present several efficient schemes for generating multiphoton graph states using only one source of single or entangled pairs of photons and delay lines.

Haijin Ding, Guofeng Zhang

The purpose of this article is to study the dynamics of a quantum coherent feedback network, where an$N$-level atom is coupled with a cavity and the cavity is also coupled with a single or multiple parallel waveguides. When the atom is initialized at the highest energy level, it can emit multiple photons into the cavity, and the photons can be further transmitted to the waveguides and reinteract with the cavity quantum electrodynamics (cavity-QED) system. The transmission of photons in the waveguide can construct a feedback channel with a delay determined by the length of the waveguide. We model the dynamics of the atomic and photonic states of the cavity-QED system as a linear control system with delay. By tuning the control parameters such as the coupling strengths among the atom, cavity and waveguide, the eigenstates of the quantum system can be exponentially stable or unstable, and the exponential stability of the linear quantum control system with delay is related with the generation of single- and multiphoton states. Besides, when the cavity-QED system is coupled with multiple parallel waveguides, the emitted photons oscillate among different waveguides and the stability of quantum states is influenced by the feedback loop length and coupling strengths among waveguides.

Alex Fischer, Nathan T. Arnold, Colin P. Lualdi +5 more

One of the primary challenges of photonic quantum information processing is the on-demand preparation of multiple single-photon-level quantum states from probabilistic photon pair sources. Motivated by recent developments in frequency-bin-encoded photonic quantum information processing, here we consider active time multiplexing to generate n-photon states, where n single photons with n distinct frequencies occupy the same spatiotemporal mode. We devise an approach that uses optical quantum memories to manipulate the temporal mode of heralded single photons and an array of fiber Bragg grating reflectors to jointly manipulate the frequency and temporal modes of the photons, overlapping n photons in n separate frequency bins into a single spatiotemporal mode. We calculate multiphoton state generation rates that, accounting for loss, are realistically achievable with commercially available hardware. Using only a single free-space switchable delay loop for an optical quantum memory, this scheme could feasibly produce 8-photon states at an average rate of 1 kHz.