Prime factorization of an integer is possible in polynomial time by a quantum computer

Evidence for a limited quantum speedup for template-free protein structure prediction

• Chuang et al. used molecules of chloroform molecules as a quantum computer

• Nuclear magnetic resonance was used to orient the spins of the carbon and hydrogen nuclei

• The qubit state was defined as whether the nuclei had a spin parallel or antiparallel to the external magnetic field

• Radio frequency pulses were then used to manipulate the spin states

• Ran Grover’s search algorithm

All quantum states can be expressed as a linear combination of other valid quantum states

Measurement of one particle results in its entangled particle to have a definitive result regardless of the distance between the two

• 2016: Ballance et al. used trapped-ion hyperfine qubits to demonstrate two- and single-qubit logic gates with fidelities of 99.9(1)% and 99.9934(3)% respectively.

• Continuation of Benhelm’s 2008 paper which reported fidelities of 99.3(1)% for a two-qubit gate.

• This substantial increase in fidelity means that the number of physical qubits (i.e., the trapped ions) will scale more reasonably with the number of logical qubits required for a computation

• 2014: Barends et al. demonstrated an average single-qubit gate fidelity of 99.92% and a two-qubit gate fidelity of 99.4%

• Continuation to Chow’s work in 2013 where a two-qubit gate fidelity of 96% was reported

• Barends et al. used the surface code approach for error correction which uses nearest-neighbor coupling and rapidly cycled entangled gates to enable fault tolerance

• Awschalom: NV centers consist of a substitutional nitrogen atom next to a missing carbon atom in a diamond lattice

• At the carbon vacancy, six electrons are trapped whose spin can be using as a qubit

• Electron spins are also coupled to nuclear spins which can together form a single node in a quantum computer

• Maintain spin coherence through wide range of temperatures, including room temperature!

• High potential for scalability

  • Nodes connected optically