2012/08/31 by Zhan Shi, C. B. Simmons, Daniel R. Ward +13 · 107 citations
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Asymmetry #Atomic physics #Charge (physics) #Charge qubit #Condensed matter physics #Dephasing #Echo (communications protocol) #Noise (video) #Phase qubit #Physics #Quantum #Quantum and electron transport phenomena #Quantum decoherence #Quantum mechanics #Qubit #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physrevb.88.075416
published in Physical Review B 88(7) (American Physical Society) · 5 pages plus 3 page supplemental (8 pages total)
arxiv created 2013/07/18 · openalex publication_date 2013/08/13 · arxiv updated 2013/08/14 · openalex created_date 2016/08/23 · openalex updated_date 2026/08/05
Fast quantum oscillations of a charge qubit in a double quantum dot fabricated in a Si/SiGe heterostructure are demonstrated and characterized experimentally. The measured inhomogeneous dephasing time T2* ranges from 127 ps to 2.1 ns; it depends substantially on how the energy difference of the two qubit states varies with external voltages, consistent with a decoherence process that is dominated by detuning noise (charge noise that changes the asymmetry of the qubit's double-well potential). In the regime with the shortest T2*, applying a charge-echo pulse sequence increases the measured inhomogeneous decoherence time from 127 to 760 ps, demonstrating that low-frequency noise processes are an important dephasing mechanism.