Coherent manipulation of semiconductor quantum bits with terahertz radiation

Abstract

Quantum bits (qubits) are the fundamental building blocks of quantum information processors, such as quantum computers. A qubit comprises a pair of well characterized quantum states that can in principle be manipulated quickly compared to the time it takes them to decohere by coupling to their environment. Much remains to be understood about the manipulation and decoherence of semiconductor qubits. Here we show that hydrogen-atom-like motional states of electrons bound to donor impurities in currently available semiconductors can serve as model qubits. We use intense pulses of terahertz radiation to induce coherent, damped Rabi oscillations in the population of two low-lying states of donor impurities in GaAs. Our observations demonstrate that a quantum-confined extrinsic electron in a semiconductor can be coherently manipulated like an atomic electron, even while sharing space with approximately 10(5) atoms in its semiconductor host. We anticipate that this model system will be useful for measuring intrinsic decoherence processes, and for testing both simple and complex manipulations of semiconductor qubits.

Quantum path control on the harmonic emission in the presence of a terahertz field

“…Recently, the fast development of the terahertz technology [21,22] has made it possible to obtain an extremely strong and long-wavelength THz field [23,26]. Based on this, a new scheme with the coherent THz control to HHG generation has been put forward and widely investigated [24][25][26][27].…”

Electric field ionization of gallium acceptors in germanium induced by single-cycle terahertz pulses

“…1 The ability to induce nonlinear interactions of impurity states with high-power THz pulses has opened up the possibility of coherent manipulation of quantum bits in ubiquitous semiconductors. 2,3 For ultrafast coherent manipulation of impurity states, the duration of the controlling THz pulse should be shorter than the coherence time. 4 Simultaneously, in order to keep the pulse area large enough for inducing a population inversion, the peak electric field of the controlling pulse must be intense.…”

Silicon-based spin and charge quantum computation

“…Successful coherent manipulation of electron orbital states in GaAs has been achieved for electrons bound to donor impurities (Cole et al 2000) as well as electrons in double quantum dots (Hayashi et al 2003). There were also suggestions of directly using electron orbital states in Si as the building blocks for quantum information processing (Hollenberg et al 2004a, b).…”