Qubit regularization is a procedure to regularize the infinite dimensional local Hilbert space of bosonic fields finite one, which crucial step when trying simulate lattice quantum field theories on computer. When qubit-regularized preserve important symmetries original theory, qubit naturally enforces certain algebraic structures these fields. We introduce concept embedding algebras (QEAs) cha...

Quantum measurement is universal for quantum computation (Nielsen [2], Leung [3,4]). The model of quantum computation introduced by Nielsen and further developed by Leung relies on a generalized form of teleportation. In order to simulate any n-qubit unitary transformation with this model, 4 auxiliary qubits are required. Moreover Leung exhibited a universal family of observables composed of 4 ...

We show how, given any set of generators of the stabilizer of a quantum code, an eecient gate array that computes the codewords can be constructed. For an n-qubit code whose stabilizer has d generators, the resulting gate array consists of O(nd) operations, and converts k-qubit data (where k = n ? d) into n-qubit codewords.

In many physically realistic models of quantum computation, Pauli exchange interactions cause a subset of 2-qubit errors to occur as a first-order effect of couplings within the computer, even in the absence of interactions with the computer's environment. We give an explicit 9-qubit code that corrects both Pauli exchange errors and all 1-qubit errors.

The persistent current qubit is a superconducting ring interrupted by three Josephson junctions. Its two quantum states have circulating currents in opposite directions which can be measured by a dc SQUID magnetometer. This work examines a persistent current qubit fabricated in niobium, using Lincoln Laboratory's DPARTS process. Measurements of the niobium qubit show a promisingly high subgap r...

This paper proposes a novel genetic quantum algorithm (GQA) to solve geometric constraint problems. Instead of binary, numeric or symbolic representation, we introduce qubit chromosome representation. GQA is based on qubit and superposition of states and is used in the process of geometric constraint solving in order to get the solution sequence. As GQA has diversity caused by the qubit represe...

We generalize the dispersive theory of the Jaynes-Cummings model beyond the frequently employed rotating-wave approximation RWA in the coupling between the two-level system and the resonator. For a detuning sufficiently larger than the qubit-oscillator coupling, we diagonalize the non-RWA Hamiltonian and discuss the differences to the known RWA results. Our results extend the regime in which di...

The requirement of performing both single-qubit and two-qubit operations in the implementation of universal quantum logic often leads to very demanding constraints on quantum computer design. We show here how to eliminate the need for single-qubit operations in a large subset of quantum computer proposals: those governed by isotropic and XXZ, XY-type anisotropic exchange interactions. Our metho...

The interference between repeated Landau-Zener transitions in a qubit swept through an avoided level crossing results in Stückelberg oscillations in qubit magnetization, a hallmark of the coherent strongly driven regime in two-level systems. The two-dimensional Fourier transforms of the resulting oscillatory patterns are found to exhibit a family of one-dimensional curves in Fourier space, in a...