Loss-resistant state teleportation and entanglement swapping using a quantum-dot spin in an optical microcavity

Abstract

We present a scheme for efficient state teleportation and entanglement swapping using a single quantum-dot spin in an optical microcavity based on giant circular birefringence. State teleportation or entanglement swapping is heralded by the sequential detection of two photons, and is finished after the spin measurement. The spin-cavity unit works as a complete Bell-state analyzer with a built-in spin memory allowing loss-resistant repeater operation. This device can work in both the weak coupling and the strong coupling regime, but high efficiencies and high fidelities are only achievable when the side leakage and cavity loss is low. We assess the feasibility of this device, and show it can be implemented with current technology. We also propose a spin manipulation method using single photons, which could be used to preserve the spin coherence via spin echo techniques.

Universal remote quantum computation assisted by the cavity input–output process

“…As shown in figures 8 and 9, high fidelity and efficiency may be achieved even in the weakly coupling regime C < 100 when the cavity side leakage ratio κ s /κ → 0. Otherwise, strong coupling is necessary [32,61,66,67]. Fortunately, strong coupling has been realized up to 2.4 [65] in 1.5 µm micropillar microcavities.…”

“…Conversely, if the excess electron spin is in the state | ↓ , after reflection the pulse |R gets a phase shift of θ h while the pulse |L gets a phase shift of θ 0 . Generally, for initial electron spin in the state α 2 | ↑ + β 2 | ↓ , the optical interaction leads to the following transformation [32,40,50,52]:…”

Optically controlled phase gate and teleportation of a controlled-not gate for spin qubits in a quantum-dot–microcavity coupled system

“…Furthermore, the charge dynamics dependent on the spin state of an electron could be optically induced via the Pauli exclusion principle and optical selection rules. Much effort has been dedicated to investigating fast initialization of the spin state of a single electron [20,21], fast spin nondestructive measurement [22], and fast optical control and coherent manipulation of a QD spin [23,24] and to demonstrating the implementations of optically controlled single-bit rotation gate and two-bit quantum phase gate for spin qubits in QDs [25][26][27][28][29][30][31][32].…”

Scheme for Implementing Controlled Quantum Teleportation in QDS-Cavity System

“…in the past years. Therefore, the principles of quantum mechanics have supplied much theoretical support in the field of quantum information, such as quantum communication and computation (Ralph and Lam 2009;Reid et al 2009;Lund, Ralph, and Haselgrove 2008;Gu et al 2009;Lloyd 2008), quantum key distribution and secret sharing (Grosshans et al 2003), quantum error correction (Steane 1996;Shor 1995), quantum teleportation (Sherson et al 2006;Hu and Rarity 2011) and quantum memory (Jensen et al 2011;Lvovsky, Sanders, and Tittel 2009) and so on. Especially, quantum teleportation is an important branch of quantum information and it is a technique for transferring quantum states from one place to another without moving through the intervening space.…”

“…Up to now, many experimental schemes for realizing quantum teleportation have been performed by virtue of optical systems (Sherson et al 2006), NMR techniques (Nielsen, Knill, and Laflamme 1998), and quantum dot system (Hu and Rarity 2011) and so on. The idea of using spins in quantum dots (QDs) for quantum information processing (QIP) has become very promising and interesting since the seminal work of Loss and Divincenzo (Loss and Divincenzo 1998) and papers of Obermayer, Teich, and Mahler (1988).…”