Charge qubit

Charge qubit
Circuit diagram of a Cooper pair box circuit. The island (dotted line) is formed by the superconducting electrode between the gate capacitor and the junction capacitance.

In quantum computing, a charge qubit is a superconducting qubit whose basis states are charge states (i.e. states which represent the presence or absence of excess Cooper pairs in the island). A charge qubit is formed by a tiny superconducting island (also known as a Cooper-pair box) coupled by a Josephson junction to a superconducting reservoir (see figure). The state of the qubit is determined by the number of Cooper pairs which have tunneled across the junction. In contrast with the charge state of an atomic or molecular ion, the charge states of such an "island" involve a macroscopic number of conduction electrons of the island. The quantum superposition of charge states can be achieved by tuning the gate voltage U that controls the chemical potential of the island. The charge qubit is typically read-out by electrostatically coupling the island to an extremely sensitive electrometer such as the radio-frequency single-electron transistor.

Typical T1 times for a charge qubit are on the order of 1-2 μs.

References


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • Flux qubit — In quantum computing, flux qubits (also known as persistent current qubits) are micrometer sized loops of superconducting metal interrupted by a number of Josephson junctions. The junction parameters are engineered during fabrication so that a… …   Wikipedia

  • One-Shot Entanglement-Enhanced Classical Communication — In the theory of quantum communication, it is well known that entanglement cannot increase the capacity of a classical communication channel in the sense of Shannon, that is, for an i.i.d. (independent and identically distributed) protocol.… …   Wikipedia

  • Nitrogen-vacancy center — The nitrogen vacancy center (N V center) is one of numerous point defects in diamond. Its most explored and useful property is photoluminescence, which can be easily detected from an individual N V center. Electron spins at N V centers, localized …   Wikipedia

  • Deutsch–Jozsa algorithm — The Deutsch–Jozsa algorithm is a quantum algorithm, proposed by David Deutsch and Richard Jozsa in 1992[1] with improvements by Richard Cleve, Artur Ekert, Chiara Macchiavello, and Michele Mosca in 1998.[2] Although it is of little practical use …   Wikipedia

  • Quantum information — For the journal with this title, see Historical Social Research. In quantum mechanics, quantum information is physical information that is held in the state of a quantum system. The most popular unit of quantum information is the qubit, a two… …   Wikipedia

  • Quantum channel — In quantum information theory, a quantum channel is a communication channel which can transmit quantum information, as well as classical information. An example of quantum information is the state of a qubit. An example of classical information… …   Wikipedia

  • One-way quantum computer — The one way or measurement based quantum computer is a method of quantum computing that first prepares an entangled resource state, usually a cluster state or graph state, then performs single qubit measurements on it. It is one way because the… …   Wikipedia

  • Quantum finite automata — In quantum computing, quantum finite automata or QFA are a quantum analog of probabilistic automata. They are related to quantum computers in a similar fashion as finite automata are related to Turing machines. Several types of automata may be… …   Wikipedia

  • Nuclear magnetic resonance quantum computer — Molecule of alanine used in NMR implementation of quantum computing. Qubits are implemented by spin states of the black carbon atoms NMR quantum computing uses the spin states of molecules as qubits. NMR differs from other implementation …   Wikipedia

  • Optical lattice — Simulation of an optical lattice potential. An optical lattice is formed by the interference of counter propagating laser beams, creating a spatially periodic polarization pattern. The resulting periodic potential may trap neutral atoms via the… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”