Hyper-parallel photonic quantum computation with coupled quantum dots

Abstract

It is well known that a parallel quantum computer is more powerful than a classical one. So far, there are some important works about the construction of universal quantum logic gates, the key elements in quantum computation. However, they are focused on operating on one degree of freedom (DOF) of quantum systems. Here, we investigate the possibility of achieving scalable hyper-parallel quantum computation based on two DOFs of photon systems. We construct a deterministic hyper-controlled-not (hyper-CNOT) gate operating on both the spatial-mode and the polarization DOFs of a two-photon system simultaneously, by exploiting the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics (QED). This hyper-CNOT gate is implemented by manipulating the four qubits in the two DOFs of a two-photon system without auxiliary spatial modes or polarization modes. It reduces the operation time and the resources consumed in quantum information processing, and it is more robust against the photonic dissipation noise, compared with the integration of several cascaded CNOT gates in one DOF.

Universal quantum gates on microwave photons assisted by circuit quantum electrodynamics

“…Many important schemes have been proposed for quantum computation by using different quantum systems, such as photonic systems [2][3][4][5][6], nuclear magnetic resonance [7,8], quantum dots [9][10][11][12], and diamond nitrogen-vacancy (NV) centers [13][14][15]. Universal quantum gates are the key elements in constructing a universal quantum computer.…”

Heralded quantum repeater for a quantum communication network based on quantum dots embedded in optical microcavities

“…In other words, the circularly polarized photon directed into the spin-cavity system can either be coupled with the electron spin and feels a hot cavity when the dipole selection rule is fulfilled, or be decoupled and feels a cold cavity in the other case. The significant difference in the reflection and the transmission coefficients manifested between these two cases is spin dependent, and it can be exploited to perform the quantum information processing [22][23][24][25][26][27][28][29][30].…”

“…Single semiconductor QD coupling to a microcavity has attracted much attention [22][23][24][25][26][27][28][29][30][31][32]. The giant circular birefringence originated from the spin selective dipole coupling for such spin-cavity systems is utilized in photon-photon or spin-photon entanglement generation [22], hyper-parallel quantum computing [23], universal quantum gates [24][25][26], hyperentanglement purification and concentration [27], and complete Bell-state analyzers [28]. In 2006, Waks and Vuckovic put forward a quantum repeater scheme with the QD-cavity system [29].…”

Hyperentanglement concentration for time-bin and polarization hyperentangled photons

“…Hyperentangled states can be used to beat the channel capacity limit of superdense coding with linear optics [23,24], construct hyper-parallel photonic quantum computing [25,26] which can reduces the operation time and the resources consumed in quantum information processing, achieve the high-capacity quantum communication with the complete teleportation and entanglement swapping in two DOFs [27,28]. They can also help to design deterministic entanglement purification protocols [29][30][31][32] which work in a deterministic way, not a probabilistic one, far different from conventional entanglement purifi- * Email address: xihanlicqu@gmail.com cation protocols [33][34][35].…”