Atomic Qubits

Bingju Zhou, Zhao-Hui Peng, Chun-Xia Jia +2 more

Considering two atomic qubits initially in Bell states, we send one qubit into a vacuum cavity with two-photon resonance and leave the other one outside. Using quantum information entropy squeezing theory, the time evolutions of the entropy squeezing factor of the atomic qubit inside the cavity are discussed for two cases, i.e., before and after rotation and measurement of the atomic qubit outside the cavity. It is shown that the atomic qubit inside the cavity has no entropy squeezing phenomenon and is always in a decoherent state before the operating atomic qubit outside the cavity. However, the periodical entropy squeezing phenomenon emerges and the optimal entropy squeezing state can be prepared for the atomic qubit inside the cavity by adjusting the rotation angle, choosing the interaction time between the atomic qubit and the cavity, controlling the probability amplitudes of subsystem states. Its physical essence is cutting the entanglement between the atomic qubit and its environment, causing the atomic qubit inside the cavity to change from the initial decoherent state into maximum coherent superposition state, which is a possible way of recovering the coherence of a single atomic qubit in the noise environment.

David K. Ferry

Anonymous

Mark E. Saffman, T. Xia, Martin Lichtman +2 more

We are exploring several different approaches towards scalable quantum computing based on neutral atom qubits with long range Rydberg blockade. Rydberg interactions can be used to entangle single atom qubits, to entangle ensemble qubits, and to establish hybrid entanglement between atomic and other qubits. Using a 2D array of atomic qubits we demonstrate high fidelity single qubit control together with entanglement of nearby qubits. The ratio of qubit coherence time to entangling gate time exceeds 1000.

Deshui Yu, L. C. Kwek, Luigi Amico A +1 more

Abstract We propose a hybrid quantum system where an LC resonator inductively interacts with a flux qubit and is capacitively coupled to a Rydberg atom. Varying the external magnetic flux bias controls the flux qubit flipping and the flux qubit-resonator interface. The atomic spectrum is tuned via an electrostatic field, manipulating the qubit-state transition of atom and the atom-resonator coupling. Different types of entanglement of superconducting, photonic and atomic qubits can be prepared via simply tuning the flux bias and electrostatic field, leading to the implementation of three-qubit Toffoli logic gate.

David S. Simon