Characterizing a high-dimensional unitary transformation without measuring the qudit it transforms
Abstract
We present a method for reconstructing an arbitrary high-dimensional unitary transformation without detecting the qudit that it transforms. We demonstrate the method using orbital angular momentum states of light. Our method relies on quantum interference enabled by the path identity of undetected photons. The method is practically useful when suitable detectors are not available for the qudit on which the unitary transformation works.
Fields of Study & Subjects
Quantum Information and Cryptography
Quantum Mechanics and Non-Hermitian Physics
Mathematical Analysis and Transform Methods
Publication details
- Journal / source
- Optics Letters
- Volume
- 51
- Issue
- 4
- Pages
- 853–853
- Publication date
- 2 January 2026
- Language
- EN