Quantum Radar.

  title={Quantum Radar.},
  author={Lorenzo Maccone and Changliang Ren},
  journal={Physical review letters},
  volume={124 20},
We propose a quantum metrology protocol for the localization of a noncooperative pointlike target in three-dimensional space, by illuminating it with electromagnetic waves. It employs all the spatial degrees of freedom of N entangled photons to achieve an uncertainty in localization that is sqrt[N] times smaller for each spatial direction than what could be achieved by N-independent photons or by classical light of the same average intensity. 

Figures from this paper

Reversible optical-microwave quantum conversion assisted by optomechanical dynamically dark modes
It is indicated that it is possible to realize the entanglement-enhanced (or suppressed) quantum conversion through controlling the phase of the initial-state parameter and the coupling ratio of the system under consideration.
Quantum technology for military applications
  • M. Krelina
  • Political Science
    EPJ Quantum Technology
  • 2021
Quantum technology is an emergent and potentially disruptive discipline, with the ability to affect many human activities. Quantum technologies are dual-use technologies, and as such are of interest
Parameter Estimation for Interrupted Sampling Repeater Jamming Based on ADMM
A computationally-effective method to estimating the parameters for ISRJ by resorting to the framework of alternating direction method of multipliers (ADMM), which exhibits much better performance in accuracy and stability than the traditional time-frequency (TF) method.


Quantum metrology.
It is proved that the typical quantum precision enhancement is of the order of the square root of the number of times the system is sampled, and it is pointed out the different strategies that permit one to attain this bound.
The elusive Heisenberg limit in quantum-enhanced metrology
It is shown that when decoherence is taken into account, the maximal possible quantum enhancement in the asymptotic limit of infinite N amounts generically to a constant factor rather than quadratic improvement.
Squeezing metrology.
Quantum metrology has up to now focused on the resolution gains obtainable thanks to the entanglement among N probes. Typically, a quadratic gain in resolution is achievable, going from the 1/sqrt(N)
Advances in quantum metrology
The statistical error in any estimation can be reduced by repeating the measurement and averaging the results. The central limit theorem implies that the reduction is proportional to the square root
Transforming spatial entanglement using a domain-engineering technique.
The far-field diffraction-interference experiments reveal that the transverse modulation of domain patterns transforms the spatial mode function of the two-photon state.
Enhanced Sensitivity of Photodetection via Quantum Illumination
It is shown that for photodetection, quantum illumination with m bits of entanglement can in principle increase the effective signal-to-noise ratio by a factor of 2m, an exponential improvement over unentangled illumination.
Positioning and clock synchronization through entanglement
An accuracy gain over analogous protocols that employ classical resources is demonstrated and a quantum-cryptographic positioning applica- tion is given, which allows only trusted par- ties to learn the position of whatever must be localized.
Quantum illumination with Gaussian states.
By making the optimum joint measurement on the light received from the target region together with the retained spontaneous parametric down-conversion idler beam, the quantum-illumination system realizes a 6 dB advantage in the error-probability exponent over the optimum reception coherent-state system.
Quantum-secured imaging
We have built an imaging system that uses a photon's position or time-of-flight information to image an object, while using the photon's polarization for security. This ability allows us to obtain an
General framework for estimating the ultimate precision limit in noisy quantum-enhanced metrology
Quantum strategies can help to make parameter-estimation schemes more precise, but for noisy processes it is typically not known how large that improvement may be. Here, a universal quantum bound is