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We demonstrated coherent control of a quantum two-level system based on two-electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout. These techniques are based on rapid electrical control of the exchange interaction. Separating and later recombining a singlet spin state provided a measurement(More)
A pulsed-gate technique with charge sensing is used to measure the singlet-triplet relaxation time for nearly degenerate spin states in a two-electron double quantum dot. Transitions from the ͑1,1͒ charge occupancy state to the ͑0,2͒ state, measured as a function of pulse cycle duration and magnetic field, allow the ͑1,1͒ singlet-triplet relaxation time(More)
Visceral pain describes pain emanating from the thoracic, pelvic, or abdominal organs. In contrast to somatic pain, visceral pain is generally vague, poorly localized, and characterized by hypersensitivity to a stimulus such as organ distension. Animal models have played a pivotal role in our understanding of the mechanisms underlying the pathophysiology of(More)
BACKGROUND & AIMS 5-hydroxytryptamine receptor (5-HT(4)R) agonists promote gastrointestinal motility and attenuate visceral pain, but concerns about adverse reactions have restricted their availability. We tested the hypotheses that 5-HT(4) receptors are expressed in the colonic epithelium and that 5-HT(4)R agonists can act intraluminally to increase(More)
The spin of a confined electron, when oriented originally in some direction, will lose memory of that orientation after some time. Physical mechanisms leading to this relaxation of spin memory typically involve either coupling of the electron spin to its orbital motion or to nuclear spins. Relaxation of confined electron spin has been previously measured(More)
Singlet-triplet spin blockade in a few-electron lateral double quantum dot is investigated using simultaneous transport and charge-sensing measurements. Transport from the ͑1,1͒ to the ͑0,2͒ electron occupancy states is strongly suppressed relative to the opposite bias ͓͑0,2͒–͑1,1͔͒. At large bias, spin blockade ceases as the ͑0,2͒ triplet state enters the(More)
BACKGROUND Although visceral pain of gastrointestinal (GI) origin is the major complaint in patients with irritable bowel syndrome (IBS) it remains poorly understood. Brain imaging studies suggest a defect in brain-gut communication in IBS with a greater activation of central arousal circuits including the amygdala. Previously, we found that stereotaxic(More)
We manipulate a single electron in a fully tunable double quantum dot using microwave excitation. Under resonant conditions, microwaves drive transitions between the (1,0) and (0,1) charge states of the double dot. Local quantum point contact charge detectors enable a direct measurement of the photon-induced change in occupancy of the charge states. From(More)
The mechanisms underlying the cause and treatment of visceral pain of gastrointestinal origin are poorly understood. Previous clinical studies have shown that spinal cord stimulation (SCS) attenuates neuropathic and ischemic pain, and animal experiments have provided knowledge about probable physiological mechanisms. The goal of the present study was to(More)
Recent experiments have demonstrated quantum manipulation of two-electron spin states in double quantum dots using electrically controlled exchange interactions. Here we present a detailed theory for electron-spin dynamics in two-electron double-dot systems that was used to guide those experiments and analyze the results. Specifically, we analyze both(More)