TY - JOUR
T1 - Bang-bang control of fullerene qubits using ultrafast phase gates
AU - Morton, John J.L.
AU - Tyryshkin, Alexei M.
AU - Ardavan, Arzhang
AU - Benjamin, Simon C.
AU - Porfyrakis, Kyriakos
AU - Lyon, S. A.
AU - Briggs, G. Andrew D.
PY - 2006/1/15
Y1 - 2006/1/15
N2 - Quantum mechanics permits an entity, such as an atom, to exist in a superposition of multiple states simultaneously. Quantum information processing (QIP) harnesses this profound phenomenon to manipulate information in radically new ways. A fundamental challenge in all QIP technologies is the corruption of superposition in a quantum bit (qubit) through interaction with its environment. Quantum bang-bang control provides a solution by repeatedly applying 'kicks' to a qubit, thus disrupting an environmental interaction. However, the speed and precision required for the kick operations has presented an obstacle to experimental realization. Here we demonstrate a phase gate of unprecedented speed on a nuclear spin qubit in a fullerene molecule, and use it to bang-bang decouple the qubit from a strong environmental interaction. We can thus trap the qubit in closed cycles on the Bloch sphere, or lock it in a given state for an arbitrary period. Our procedure uses operations on a second qubit, an electron spin, to generate an arbitrary phase on the nuclear qubit. We anticipate that the approach will be important for QIP technologies, especially at the molecular scale where other strategies, such as electrode switching, are unfeasible.
AB - Quantum mechanics permits an entity, such as an atom, to exist in a superposition of multiple states simultaneously. Quantum information processing (QIP) harnesses this profound phenomenon to manipulate information in radically new ways. A fundamental challenge in all QIP technologies is the corruption of superposition in a quantum bit (qubit) through interaction with its environment. Quantum bang-bang control provides a solution by repeatedly applying 'kicks' to a qubit, thus disrupting an environmental interaction. However, the speed and precision required for the kick operations has presented an obstacle to experimental realization. Here we demonstrate a phase gate of unprecedented speed on a nuclear spin qubit in a fullerene molecule, and use it to bang-bang decouple the qubit from a strong environmental interaction. We can thus trap the qubit in closed cycles on the Bloch sphere, or lock it in a given state for an arbitrary period. Our procedure uses operations on a second qubit, an electron spin, to generate an arbitrary phase on the nuclear qubit. We anticipate that the approach will be important for QIP technologies, especially at the molecular scale where other strategies, such as electrode switching, are unfeasible.
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U2 - 10.1038/nphys192
DO - 10.1038/nphys192
M3 - Article
AN - SCOPUS:33646340649
SN - 1745-2473
VL - 2
SP - 40
EP - 43
JO - Nature Physics
JF - Nature Physics
IS - 1
ER -