The quantum computational speed of a single Cooper-pair box

Abstract

The speed of computations is investigated by means of the orthogonality speed for a charged qubit interacting with a single cavity field prepared initially in a Fock state or Binomial state. We observe that the rate of the computational speed is related to the number of photons inside the cavity. Moreover, we show that the qubit-field coupling plays an opposite role, where the speed of computations is decreased as the coupling is increased. We suggest using the number of photons in the field as a control parameter to improve the speed of computations. pacs74.70.-b, 03.65.Ta, 03.65.Yz, 03.67.-a, 42.50.-p e 2 2(Cg +C J ) dominate over the Josephson coupling energy E J , and concentrate on the value V g = e Cg and weak

Dynamical Properties of Multi-Photon Interaction Between a Cavity Field and a Single-Qubit

“…13,18 Suppose that the gate capacitance C g is screened from the quantized radiation¯eld, and the system can be described by a two-level system with Hamiltonian. 20,22,26,27 …”

Using a hybrid system (Cooper pair box plus nanomechanical resonator) in the presence of Kerr nonlinearities and losses to control the entropy of the subsystems

“…The interaction of the single photon field with superconducting circuit to generate quantum bits is studied experimentally [1,2] and theoretically [3][4][5]. Wallraff et al have observed a strong coupling between the superconducting two-level system and a single microwave photon which prove the generation of qubits.…”

Mutual entropy of a single Cooper pair-box interacting with multi-photon field

“…The interaction of the single photon field with superconducting circuit to generate quantum bits is studied experimentally [15], [16] and theoretically [24], [25], [26]. Wallraff et al have observed a strong coupling and coherent between the superconducting two-level system with a single microwave photon which prove that the qubits is generated.…”

“…The resulting entanglement in this system is quantified using different measures [24]. The optimum parameters of the system to be used in the quantum teleportation process [33], speed of computations [25] and dynamics of the coded information [26] are investigated. The dynamical properties of the interaction of the single cooper pair box with two cavity field is studied [34].…”