What is recorded here?
Angulo and colleagues measured the small phase shift of an off-resonant probe caused by resonant light passing through a cold rubidium cloud. Comparing probe traces with and without a later photon detection isolated the inferred contribution of an extra transmitted photon. For longer, narrower-band pulses, its integrated response had the opposite sign to the average-photon response. The authors interpreted this result as evidence for a negative conditional atomic-excitation time related to anomalous group delay.
Source-linked catalogue note. A detailed explanatory guide has not yet been prepared for this entry.
Scientific scope
The experiment used coherent light, weak probing and post-selection, with finite integration windows and reported statistical and systematic uncertainties. A conditional weak response is distinct from the always nonnegative unconditional excited-state population. Some data disagree quantitatively with the theory, and a bypass control retains a residual signal. The observation does not demonstrate time travel or superluminal information transfer. The cited preprint and supplement date from 2024; the 2026 journal version may differ.
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People and systems
Daniela Angulo; Kyle Thompson; Vida-Michelle Nixon; Andy Jiao; Howard M. Wiseman; Aephraim M. Steinberg
These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
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English catalogue narrative
A post-selected optical measurement yields negative conditional atomic-excitation response
Angulo and colleagues measured the small phase shift of an off-resonant probe caused by resonant light passing through a cold rubidium cloud. Comparing probe traces with and without a later photon detection isolated the inferred contribution of an extra transmitted photon. For longer, narrower-band pulses, its integrated response had the opposite sign to the average-photon response. The authors interpreted this result as evidence for a negative conditional atomic-excitation time related to anomalous group delay.
Scientific scope
The experiment used coherent light, weak probing and post-selection, with finite integration windows and reported statistical and systematic uncertainties. A conditional weak response is distinct from the always nonnegative unconditional excited-state population. Some data disagree quantitatively with the theory, and a bypass control retains a residual signal. The observation does not demonstrate time travel or superluminal information transfer. The cited preprint and supplement date from 2024; the 2026 journal version may differ.
Reading status
This is a source-linked WRS catalogue note. A full explanatory guide and independent scientific reconstruction have not been completed for this entry. Read the identified original work for its complete narrative and arguments.
People and systems
Daniela Angulo; Kyle Thompson; Vida-Michelle Nixon; Andy Jiao; Howard M. Wiseman; Aephraim M. Steinberg
These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.