Measuring the time atoms spend in the excited state due to a photon they don't absorb

• URL: http://arxiv.org/abs/2010.02200v1
• Date: Mon, 5 Oct 2020 17:59:06 GMT
• Title: Measuring the time atoms spend in the excited state due to a photon they don't absorb
• Authors: Josiah Sinclair, Daniela Angulo, Kyle Thompson, Kent Bonsma-Fisher, Aharon Brodutch, and Aephraim M. Steinberg
• Abstract summary: In an experiment with ultra-cold Rubidium atoms, we simultaneously record whether atoms are excited by incident photons and whether those photons are transmitted. We find that the average time atoms spend in the excited state due to one transmitted photon is not zero, but rather (77 $pm$ 16)% of the time the average incident photon causes them to spend in the excited state.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: When a resonant photon traverses a sample of absorbing atoms, how much time do atoms spend in the excited state? Does the answer depend on whether the photon is ultimately absorbed or transmitted? In particular, if it is $\textit{not}$ absorbed, does it cause atoms to spend any time in the excited state, and if so, how much? In an experiment with ultra-cold Rubidium atoms, we simultaneously record whether atoms are excited by incident ("signal") photons and whether those photons are transmitted. We measure the time spent by atoms in the excited state by using a separate, off-resonant "probe" laser to monitor the index of refraction of the sample - that is, we measure the nonlinear phase shift written by a signal pulse on this probe beam - and use direct detection to isolate the effect of single transmitted photons. For short pulses (10 ns, to be compared to the 26 ns atomic lifetime) and an optically thick medium (peak OD = 4, leading to 60% absorption given our broad bandwidth), we find that the average time atoms spend in the excited state due to one transmitted photon is not zero, but rather (77 $\pm$ 16)% of the time the average incident photon causes them to spend in the excited state. We attribute this observation of "excitation without loss" to coherent forward emission, which can arise when the instantaneous Rabi frequency (pulse envelope) picks up a phase flip - this happens naturally when a broadband pulse propagates through an optically thick medium with frequency-dependent absorption [1]. These results unambiguously reveal the complex history of photons as they propagate through an absorbing medium and illustrate the power of utilizing post-selection to experimentally investigate the past behaviour of observed quantum systems.

Related papers

• Experimental evidence that a photon can spend a negative amount of time in an atom cloud [0.0]
  We use the cross-Kerr effect to probe the degree of atomic excitation caused by a resonant transmitted photon. Our results are consistent with the recent theoretical prediction that the mean atomic excitation time caused by a transmitted photon equals the group delay experienced by the light.
  arXiv  Detail & Related papers  (2024-09-05T16:32:50Z)
• Collectively induced transparency and absorption in waveguide QED with Bragg atom arrays [0.5463417677777277]
  We study collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous frequencies. For atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. We find collectively induced absorption (CIA) by studying the influence of free-space dissipation on photon transport.
  arXiv  Detail & Related papers  (2024-07-06T02:30:54Z)
• How much time does a photon spend as an atomic excitation before being transmitted? [0.0]
  We show that the time a transmitted photon spends as an atomic excitation is equal to the group delay. We also determine the corresponding time for scattered photons and find that it is equal to the time delay of the scattered photon pulse.
  arXiv  Detail & Related papers  (2023-09-30T16:49:21Z)
• Correlated steady states and Raman lasing in continuously pumped and probed atomic ensembles [68.8204255655161]
  We consider an ensemble of Alkali atoms that are continuously optically pumped and probed. Due to the collective scattering of photons at large optical depth, the steady state of atoms does not correspond to an uncorrelated tensor-product state. We find and characterize regimes of Raman lasing, akin to the model of a superradiant laser.
  arXiv  Detail & Related papers  (2022-05-10T06:54:54Z)
• Direct observation of photon bound states using a single artificial atom [0.45507178426690204]
  We report the direct observation of a photon-number-dependent time delay in the scattering off a single semiconductor quantum dot coupled to an optical cavity. The reduced time delay of the two-photon bound state is a fingerprint of the celebrated example of stimulated emission, where the arrival of two photons within the lifetime of an emitter causes one photon to stimulate the emission of the other from the atom.
  arXiv  Detail & Related papers  (2022-05-06T15:41:59Z)
• Dynamics of Transmon Ionization [94.70553167084388]
  We numerically explore the dynamics of a driven transmon-resonator system under strong and nearly resonant measurement drives. We find clear signatures of transmon ionization where the qubit escapes out of its cosine potential.
  arXiv  Detail & Related papers  (2022-03-21T18:00:15Z)
• Investigating the coherent state detection probability of InGaAs/InP SPAD-based single-photon detectors [55.41644538483948]
  We investigate the probabilities of detecting single- and multi-photon coherent states on InGaAs/InP sine-gated and free-run avalanche diodes. We conclude that multi-photon state detection cannot be regarded as independent events of absorption of individual single-photon states.
  arXiv  Detail & Related papers  (2021-04-16T08:08:48Z)
• Motion-induced radiation due to an atom in the presence of a graphene plane [62.997667081978825]
  We study the motion-induced radiation due to the non-relativistic motion of an atom in the presence of a static graphene plate. We show that the effect of the plate is to increase the probability of emission when the atom is near the plate and oscillates along a direction perpendicular to it.
  arXiv  Detail & Related papers  (2021-04-15T14:15:23Z)
• Quantum theory of Rayleigh scattering [0.0]
  Scattering is considered as a relaxation of incident photons from a selected mode of free space to the reservoir of the other free space modes. We show that an entangled state of the excited atom and the incident photon is formed during the scattering.
  arXiv  Detail & Related papers  (2020-10-22T16:30:53Z)
• A bright and fast source of coherent single photons [46.25143811066789]
  A single photon source is a key enabling technology in device-independent quantum communication. We report a single photon source with an especially high system efficiency.
  arXiv  Detail & Related papers  (2020-07-24T17:08:46Z)
• Quantum time dilation in atomic spectra [62.997667081978825]
  We demonstrate how quantum time dilation manifests in a spontaneous emission process. The resulting emission rate differs when compared to the emission rate of an atom prepared in a mixture of momentum wave packets. We argue that spectroscopic experiments offer a technologically feasible platform to explore the effects of quantum time dilation.
  arXiv  Detail & Related papers  (2020-06-17T18:03:38Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.