Quantum state tomography of undetected photons

Abstract

The measurement of quantum states is one of the most important problems in quantum mechanics. We introduce a quantum state tomography technique in which the state of a qubit is reconstructed, while the qubit remains undetected. The key ingredients are: (i) employing an additional qubit, (ii) aligning the undetected qubit with a known reference state by using path identity, and (iii) measuring the additional qubit to reconstruct the undetected qubit state. We theoretically establish and experimentally demonstrate the method with photonic polarization states. The principle underlying our method could also be applied to quantum entities other than photons.

6 pages, 4 figures + 4 pages, 2 figures

References in corpus (6)

• Experimental Quantum State Tomography of Optical Fields and Ultrafast Statistical Sampling
• Private Randomness Expansion With Untrusted Devices
• Quantifying the Momentum Correlation between Two Light Beams by Detecting One
• Quantum Imaging for Semiconductor Industry
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Cited by in corpus (3)

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• Visibility Stokes parameters as a foundation for quantum information science with undetected photons