| name | quantum-limited-subdiffraction-telescopy |
| description | Quantum-limited subdiffraction telescopy using genuine multi-telescope interference. Proves pairwise measurements insufficient for higher-order image moment estimation at quantum limit. Constructs array-SPADE measurements attaining optimal QFI scaling up to finite-array cutoff. Applicable to quantum metrology, astronomical imaging, quantum network telescopy, and spatial-mode demultiplexing. |
| metadata | {"arxiv_id":"2606.27276","published":"2026-06-25","authors":"Yujie Zhang, Yunkai Wang, Wilson Wu, Thomas Jennewein","tags":["quantum","information-theory","telescopy","quantum-fisher-information","SPADE","multi-telescope","interferometry","imaging"]} |
Quantum-Limited Subdiffraction Telescopy via Multi-Telescope Interference
Overview
Conventional stellar interferometry reconstructs incoherent sources from pairwise mutual coherences. For generic image-moment estimation, pairwise measurements are not sufficient for quantum-limited subdiffraction imaging.
Core Theory
Quantum Fisher Information Scaling
For an N-telescope array observing weak incoherent light from a generic extended source:
- QFI scaling of image moments: derived up to cutoff 2N-2
- Pairwise measurements attain full-array QFI scaling only up to second order
- Higher-order moment estimation at the quantum limit requires genuinely multi-telescope interference
Key Result
| Measurement Type | Max Order Attaining Full QFI |
|---|
| Telescope pairs | 2nd order |
| Full N-array | 2N-2 |
The gap between pairwise and full-array capability grows with array size.
array-SPADE Construction
Inspired by spatial-mode demultiplexing (SPADE) from single-aperture subdiffraction imaging:
- Construct array-SPADE measurements
- Attain optimal QFI scaling up to finite-array cutoff
- Embeddable in ancilla- and memory-assisted quantum-network architectures for long-baseline telescopy
Methodology
When Pairwise Is Insufficient
- Determine the order of image moment to estimate
- If order > 2, pairwise coherence measurements lose QFI scaling
- Design multi-telescope interference measurement
array-SPADE Implementation Steps
- Map each telescope's optical mode to the array-SPADE basis
- Perform joint measurement across all N modes simultaneously
- Extract image moments up to order 2N-2
- Use ancilla-assisted protocols for long-baseline operation
Pitfalls
- Pairwise sufficiency misconception: Many papers assume pairwise coherence measurements are sufficient for arbitrary resolution enhancement — this paper proves they are not for higher-order moments
- Memory requirement: Multi-telescope interference requires quantum memory/ancilla for long baselines where light arrives asynchronously
- Finite cutoff: QFI scaling has fundamental cutoff at 2N-2 for N telescopes — cannot estimate arbitrarily high-order moments regardless of measurement sophistication
Related Papers
- SPADE (single-aperture spatial-mode demultiplexing)
- Quantum Fisher Information estimation under decoherence
- Multi-mode entangling-gate synthesis in trapped-ion systems (2606.27266)
Activation
Keywords: quantum telescopy, subdiffraction imaging, quantum Fisher information, array-SPADE, multi-telescope interference, stellar interferometry, image-moment estimation, quantum-limited resolution, spatial-mode demultiplexing
