Experimentally probing anomalous time evolution of a single photon.

Area of Science:

• Quantum Mechanics
• Quantum Information Science
• Experimental Physics

Background:

• Quantum systems collapse upon measurement, making their time evolution difficult to study.
• Anomalous quantum phenomena, like particles seemingly disappearing and reappearing, require precise investigation.
• Weak values (WVs) offer a method to probe quantum systems, but their interpretation can be complex.

Purpose of the Study:

• To experimentally investigate anomalous quantum time evolution of a single photon.
• To probe the time evolution using sequential weak values (SWVs) and higher-order correlations.
• To develop and demonstrate a novel probeless measurement scheme for multi-operator WVs.

Main Methods:

• Directly probed the time evolution of a single photon.
• Measured up to triple-operator sequential weak values (SWVs).
• Employed a novel probeless measurement scheme.

Main Results:

• Single-operator WVs suggested a photon's "disappearance" and "re-appearance."
• Double- and triple-operator SWVs demonstrated that spatial information does not fully vanish intermediately.
• Higher-order temporal correlations are essential for a complete understanding of quantum time evolution.

Conclusions:

• Local values (single-operator WVs) are insufficient to explain all quantum time evolution.
• Higher-order correlations are generally necessary to fully describe quantum phenomena.
• The proposed probeless technique for measuring multi-operator WVs is extendable to other quantum systems.