13,863 research outputs found
Braid Topologies for Quantum Computation
In topological quantum computation, quantum information is stored in states
which are intrinsically protected from decoherence, and quantum gates are
carried out by dragging particle-like excitations (quasiparticles) around one
another in two space dimensions. The resulting quasiparticle trajectories
define world-lines in three dimensional space-time, and the corresponding
quantum gates depend only on the topology of the braids formed by these
world-lines. We show how to find braids that yield a universal set of quantum
gates for qubits encoded using a specific kind of quasiparticle which is
particularly promising for experimental realization.Comment: 4 pages, 4 figures, minor revision
Constructing Quantum Logic Gates Using q-Deformed Harmonic Oscillator Algebras
We study two-level q-deformed angular momentum states and us- ing q-deformed
harmonic oscillators, we provide a framework for con- structing qubits and
quantum gates. We also present the construction of some basic quantum gates
including CNOT, SWAP, Toffoli and Fredkin.Comment: Slightly modified version of the accepted manuscrip
Optical holonomic single quantum gates with a geometric spin under a zero field
Realization of fast fault-tolerant quantum gates on a single spin is the core
requirement for solid-state quantum-information processing. As polarized light
shows geometric interference, spin coherence is also geometrically controlled
with light via the spin-orbit interaction. Here, we show that a geometric spin
in a degenerate subspace of a spin-1 electronic system under a zero field in a
nitrogen vacancy center in diamond allows implementation of optical
non-adiabatic holonomic quantum gates. The geometric spin under quasi-resonant
light exposure undergoes a cyclic evolution in the spin-orbit space, and
acquires a geometric phase or holonomy that results in rotations about an
arbitrary axis by any angle defined by the light polarization and detuning.
This enables universal holonomic quantum gates with a single operation. We
demonstrate a complete set of Pauli quantum gates using the geometric spin
preparation and readout techniques. The new scheme opens a path to holonomic
quantum computers and repeaters
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