Operational approach to indirectly measuring the tunneling time

Choi, Yunjin; Jordan, Andrew N.

doi:10.1103/physreva.88.052128

Cited by 17 publications

(12 citation statements)

References 44 publications

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“…The rest of the Bloch sphere is still occupied with a lower probability ( Fig. 5b) because of the finite time it takes for the jump to occur from one pole to the next under strong dispersive measurement rate [25]. Note how the ensemble of trajectories can go from uniform for weak measurement rates ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing

et al. 2018

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Decoherence originates from the leakage of quantum information into external degrees of freedom. For a qubit, the two main decoherence channels are relaxation and dephasing. Here, we report an experiment on a superconducting qubit where we retrieve part of the lost information in both of these channels. We demonstrate that raw averaging the corresponding measurement records provides a full quantum tomography of the qubit state where all three components of the effective spin-1/2 are simultaneously measured. From single realizations of the experiment, it is possible to infer the quantum trajectories followed by the qubit state conditioned on relaxation and/or dephasing channels. The incompatibility between these quantum measurements of the qubit leads to observable consequences in the statistics of quantum states. The high level of controllability of superconducting circuits enables us to explore many regimes from the Zeno effect to underdamped Rabi oscillations depending on the relative strengths of driving, dephasing, and relaxation.

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Section: Resultsmentioning

confidence: 99%

Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing

et al. 2018

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“…For the fully open QPC, we can generalize the Wigner surmise by combining Eqs. (37,38) and (43). We then find…”

Section: A Quantum Point Contactmentioning

confidence: 98%

Distributions of electron waiting times in quantum-coherent conductors

2014

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The distribution of electron waiting times is useful to characterize quantum transport in mesoscopic structures. Here we consider a generic quantum-coherent conductor consisting of a mesoscopic scatterer in a two-terminal setup. We extend earlier results for single-channel conductors to setups with several (possibly spin-degenerate) conduction channels and we discuss the effect of a finite electronic temperature. We present detailed investigations of the electron waiting times in a quantum point contact as well as in two mesoscopic interferometers with energy-dependent transmissions: a Fabry-P\'erot interferometer and a Mach-Zehnder interferometer. We show that the waiting time distributions allow us to determine characteristic features of the scatterers, for instance the number of resonant levels in the Fabry-P\'erot interferometer that contribute to the electronic transport.Comment: 13 pages, 11 figure

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“…Accounts of this debate can be found in a large number of reviews (see de Carvalho and Nussenzveig, 2002;Hauge and Støvneng, 1989;Landauer and Martin, 1994;Olkhovsky et al, 2004;Winful, 2006;Muga et al, 2007;Choi and Jordan, 2013). As a well-defined operator whose eigenvalue would correspond to the travel time through the classically forbidden region could not be identified, unconventional operational descriptions have been put forward, such as complex travel time based on a Feynman path integral formulation (Sokolovski et al, 1994) or contextual values replacing conventional eigenvalues of a self-adjoined operators for so-called weak measurements (Choi and Jordan, 2013). Closely related is the notion of a Larmor clock (Baz', 1967a,b;Büttiker, 1983) which yields, in general, two different precession times which can be interpreted in special cases as the real and imaginary parts of a complex time (Sokolovski et al, 1994).…”

Section: Attosecond Streaking Of Tunneling Time?mentioning

confidence: 99%

Attosecond chronoscopy of photoemission

2015

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Recent advances in the generation of well characterized sub-femtosecond laser pulses have opened up unpredicted opportunities for the real-time observation of ultrafast electronic dynamics in matter. Such attosecond chronoscopy allows a novel look at a wide range of fundamental photophysical and photochemical processes in the time domain, including Auger and autoionization processes, photoemission from atoms, molecules, and surfaces, complementing conventional energy-domain spectroscopy. Attosecond chronoscopy raises fundamental conceptual and theoretical questions as which novel information becomes accessible and which dynamical processes can be controlled and steered. These questions are currently a matter of lively debate which we address in this review. We will focus on one prototypical case, the chronoscopy of the photoelectric effect by attosecond streaking. Is photoionization instantaneous or is there a finite response time of the electronic wavefunction to the photoabsorption event? Answers to this question turn out to be far more complex and multi-faceted than initially thought. They touch upon fundamental issues of time and time delay as observables in quantum theory. We review recent progress of our understanding of time-resolved photoemission from atoms, molecules, and solids. We will highlight the unresolved and open questions and we point to future directions aiming at the observation and control of electronic motion in more complex nanoscale structures and in condensed matter.

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Operational approach to indirectly measuring the tunneling time

Cited by 17 publications

References 44 publications

Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing

Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing

Distributions of electron waiting times in quantum-coherent conductors

Attosecond chronoscopy of photoemission

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