2001/07/28 by S. W. Hwang, Sungwoo Hwang, Hwang, S. W. +14
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Quantum Information and Cryptography #Quantum Physics (quant-ph) #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #quant-ph
paper · pdf · doi:10.48550/arxiv.quant-ph/0107141
arxiv created 2001/07/28 · openalex publication_date 2001/07/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Quantum computing (or generally, quantum information processing) is of prime interest for it potentially has a significant impact on present electronics and computations1-5. Essence of quantum computing is a direct usage of the superposition and entanglement of quantum mechanical states that are pronounced in nanoscopic particles such as atoms and molecules6, 7. On the other hand, many proposals regarding the realization of semiconductor quantum dot (QD) qubits8,9 and QD quantum gates10 were reported and several experimental clues were successfully found11-16. While these pioneering experiments opened up the basis of semiconductor QD quantum computing, direct electrical control of superposed states in time domain17 has not been realized yet. Here, we demonstrate the coherent control of the superposed quantum states evolution in the QD molecule. Short electrical pulses are shown to inject single electron into the QD molecule and the current collected at the substrate exhibits oscillations as a function of the pulse width. The oscillations are originated from different decay rates of the symmetric (S) and the anti-symmetric (AS) state of the QD molecule and the evolution of the occupation probabilities controlled by the injection pulse width