Two-photon entanglement in multiqubit bidirectional-waveguide QED

Abstract

We study entanglement generation and control in bi-directional waveguide QED driven by a twophoton Gaussian wavepacket. In particular, we focus on how increasing the number of qubits affects the overall average pairwise entanglement in the system. We also investigate how the presence of a second photon can introduce non-linearities, thereby manipulating the generated entanglement. In addition, we show that through the introduction of chirality and small decay rates, entanglement can be stored and enhanced up to factors of 2 and 3, respectively. Finally, we analyze the influence of finite detunnings and time-delays on the generated entanglement.

Strong Photon Blockade Mediated by Optical Stark Shift in a Single-Atom–Cavity System

“…It offers unprecedented scientific opportunities for exploring various applications in quantum computing [6][7][8], quantum key distribution [9,10], quantum simulation [11,12], and quantum metrology [5]. Recently, the controllable singlephoton emitters have been extensively explored in different quantum systems, including atom-cavity coupled systems [13][14][15], quantum-dot-cavity coupled systems [16][17][18], coupled optomechanical systems [19][20][21], coupled optical-fiber systems [22,23], waveguide-QED systems [24][25][26][27][28], and circuit-QED systems [29][30][31], in which the quantum statistics of the output photons show a sub-Poissonian distribution due to the photon blockade (PB) [32].…”

Robust entanglement with three-dimensional nonreciprocal photonic topological insulators

“…One of the main differences between the concurrence in the reciprocal case (25), and in the unidirectional case (24), is the presence of the sinusoidal term in (25). When g 12 is strong enough, this sinusoidal term causes oscillations in the transient concurrence related to photons being recycled between the two qubits, with a period that corresponds to the round trip time of the coupled qubits through the reciprocal medium (Rabi oscillations).…”

“…In particular, there has been considerable investigation of quantum spin networks in chiral waveguides [18][19][20][21][22][23][24]. The previous work on spin dynamics in quantum chiral environments has focused on one-dimensional (1D) waveguide models.…”

Comparison of semiclassical and quantum models of a two-level atom-cavity QED system in the strong coupling regime

“…Recently, there has been novel trends in cavity QED research including, use of solid state photonic cavities with artificial atoms, such quantum dots in micro-pillar or micro-cavity resonators [26]; and circuit QED [28,29,30,31], which uses a superconducting cavity coupled to charge and flux qubits, transmons, fluxoniums, quantum dots and other atom-like entities [31,32,33,34,35,36]. Yet another novel and promising variant of cavity QED in the optical domain which utilizes a fiber waveguide as resonator has recently been developed to generate entangled photons for quantum information processing [37,38,39,40,41,42,43,44,45].…”