Structured Optical Receiver Design for Active Sensing at the Quantum Limit
Abstract
The field of quantum sensing has traditionally aimed to capitalize on nonclassical states of electromagnetic radiation, such as entangled states, to interrogate a target or region of space, and then perform conventional measurement techniques, such as direct detection or coherent detection, on the return state. While niche concepts using this approach have proven successful for narrow applications, in general, highly non-classical states are rapidly destroyed after propagating through any amount of realistic loss, such as in standoff sensing scenarios. A more robust approach to quantum sensing is to generate coherent or thermal states at the transmitter, which are eigenstates of the annihilation operator associated with loss, use those states to interrogate a target, and then make a measurement on the return state that maximizes the information that can be extracted from the state about a specific property of the target. While individual theoretical and experimental results have demonstrated receivers achieving optimal measurement of photon-starved coherent states, no foundational framework exists to realize a structured optical receiver capable of optimal measurements that achieve quantum-limited sensitivity. The effort proposed herein describes a basic research program aimed at developing formal methods for designing structured receivers that can implement quantum measurements optimized for information extraction from quantum states. This proposal to the Short-Term Innovative Research (STIR) Program, will apply this over-arching research theme to three problems: (1) optimal discrimination between coherent state and thermal state light, (2) the detection of weak coherent states within a bright thermal background, and (3) discrimination between multiple coherent amplitude states. Considering these three sensing problems we will calculate the quantum-limited sensitivity achievable using Helstrom s formulation, and determine the gap between the sensitivity achievable using traditional receivers (such as direct and coherent detection) and the quantum limit. Next, we will investigate the design of structured receivers for achieving quantum-limited sensitivity for these three sensing tasks. The technical approaches we will pursue to design these receivers are: 1. Using optical laboratory tools that are commonly applied for receiver development (displacement, squeezing, mode-sorting and photon-counting) determine how close we can get to achieving the optimal receiver operator and determine the how to implement the remaining operations necessary to implement universal optimal receivers for optical states, 2. Determine the quantum gate structure, from a set of universal quantum gates executable on a quantum computer, that can implement the optimal measurement on a received quantum state, given that they state can be efficiently coupled to a quantum register. This research effort will result in a well-defined theoretical approach for designing structured optical receivers to approach or achieve quantum-limited sensitivity for an arbitrary sensing task. Additionally, the project will result in experimental designs for demonstrating optimized receivers for the three sensing tasks proposed here.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 17, 2019
- Source ID
- W911NF1910351
Entities
People
- Jonathan Habif
Organizations
- Army Contracting Command
- United States Army
- University of Southern California