Perfect Quantum State Transfer in Glauber-Fock Cavity Array

Abstract

We study transfer of single photon in an one-dimensional finite Glauber-Fock cavity array whose coupling strengths satisfy a square root law. The evolved state in the array can be mapped to an upper truncated coherent state if the cavities are resonant. Appropriate choices of resonance frequencies provide perfect transfer of a photon between any two cavities in the array. Perfect transfer of the photon allows perfect quantum state transfer between the cavities. Our findings may help in realizing quantum communication and information processing in photonic lattices.

Quantum information processing in cavities: A review

“…Although the homogeneously coupled cavity array does not provide perfect state transfer, the array permits pretty good state transfer, that is, the fidelity of transfer becomes arbitrarily close to 1 if the number of cavities in the array is N = p − 1, 2p − 1, where p is a prime, or N = 2 m − 1 [313]. A pretty good state transfer can be achieved by tuning the coupling strengths and/or resonance frequencies [39,389,390]. For instance, if the two end cavities are loosely coupled to the array [39,390], modelled by setting J 1 = J N −1 << J l for l = 1, N − 1 in Eqn.…”

“…But the time of perfect state transfer becomes arbitrarily large [39]. Pretty good state transfer is also possible in Glauber-Fock cavity array [389], whose coupling strengths satisfy a square-root law J l = √ lJ [391][392][393][394]. The interaction term of the Hamiltonian given in Eqn.…”

“…. By properly choosing the resonance frequencies, the single-photon transfer amplitude can be calculated to be [389]…”

“…where θ depends on the resonance frequencies and coupling strengths, and becomes small for large N [389]. The time of transfer becomes large if the number of cavities in the array is large.…”

Scheme for realizing quantum dense coding via entanglement swapping

“…Due to recent progress in fabrication, it is possible to realize cavities with high quality (Q) factor. With the possibility of precise control of resonance frequencies and coupling strengths of the array, coupled cavities provide a suitable physical system for realizing many quantum information protocols [16][17][18][19][20][21][22][23]. The scalability of the array is an additional advantage for realizing distance communication.…”