US Patent 7277872 - Quantum computing with resource state

http://www.freepatentsonline.com/7277872.html

Quantum computing usually depends on entanglement between properties (e.g. polarization, spin) of fundamental particles (e.g. photons, electrons) which allows for a degree of parallel processing which is advantageous for certain computational problems. However, a problem of decoherence exists that leads to a limit in the number of fundamental particles that can be entangled. In order to overcome this problem this patent teaches a technique of using a common resource state entangled with a plurality of quantum states (as opposed to a plurality of separately entangled quantum states). Claim 1 reads:

1. A method for quantum computing, the method which comprises: providing a plurality of quantum systems each having at least two different states; preparing a resource state of the quantum systems wherein all of the quantum systems are in a common superimposed entangled state; in the resource state, making one-system measurements on the quantum systems; processing outcomes of the one-system measurements; and outputting a result of the processing.

US Patent 7230266 - Oscillation readout for quantum computing

http://www.freepatentsonline.com/7230266.html

D-Wave is a company that focuses on superconducting electronics to achieve quantum computing and currently has the largest U.S. patent portfolio in this area. Although superconducting materials can be difficult to work with if the development of a quantum computer is achieved it will open up the possibility of more exact modeling and simulation of stochastic phenomena which can be applied to economic and weather forecasting. This latest patent focuses on a reading method of a qubit using the frequency response of a quantum system. Claim 1 reads:

1. A method for determining whether a first state of a quantum system is occupied, the method comprising: (A) applying a signal to the quantum system at a frequency that corresponds to an energy level separation between said first state and a second state of said quantum system, wherein (i) said quantum system produces a readout frequency when said first state is occupied at a time when said signal is applied, and (ii) said quantum system does not produce said readout frequency when said first state is not occupied at the time when said signal is applied; and (B) measuring a property of a measurement resonator that is conditionally coupled to the quantum system when said quantum system produces said readout frequency, thereby determining whether said first state of said quantum system is occupied.