According to the United States Air Force, since 1981, 98% of stealth aircraft have gone undetected by classical radars. American airspace runs the threat of being trespassed and assaulted by foreign aircraft more and more every day as stealth technology advances.
Quantum Radar is a new step forward from classical radar, although weaker at close distances, it is able to detect stealth ships and other objects designed to avoid classical radars. Our biggest—and only—consumer base will be the DoD and private defense manufacturers such as Lockheed Martin and Raytheon, and they are greatly interested in a quantum radar that works functionally and practically. Although we don’t know for sure that the DOD has expressed interest or asked their contractors to start research or test, because it would still be classified. However, various defense contractors have filed patents related to Quantum Research, which we go into detail about in length below.
Here is the list of experts that we contacted throughout the designing process. All these experts have studied something related to quantum physics, and most have specialization with quantum radar.
Ning Bao, Northeastern
Paola Cappellaro, MIT
Shimon Kolkowitz, UC Berkeley
Mishkat Bhattacharya, RIT
Edwin Hach, RIT
Govind P. Agrawal, Rochester U
Robert Boyd, Rochester U
Brian Zhou, Boston College
Padmanabhan Aravind, WPI
William McCarthy, WPI
Leonard Khan, URI
Wenchao Ge, URI
Michael Chapman, Georgia Tech
Chunhui Du, Georgia Tech
Itamar Kimchi, Georgia Tech
Theresa W. Lynn, Harvey Mudd
Sean Carroll, Hopkins
Jefferey Shapiro, MIT
Due to the complexity of our topic we are not able to conduct any surveys, and instead conducted interviews with professors and experts.
We want to build a computer model for a quantum radar, what languages or tools would be best to start building it?
"Any professional program would viable for modeling a quantum radar, any tool you are most comfortable with will be the best for building it"
What benefits would modeling it on a quantum computer have over modeling it on a classical computer?
Classical computing is like playing a game with limited legal moves, which limits your ability to perform tests. On the other hand, Quantum Computing is like playing a game with unlimited legal moves, which benefit the accurary of your product.
For a quantum radar utilizing quantum entanglement, what would be the best way to model that, either classical or quantum?
Quantum optics is usually pretty easily modeled by a classical computer, and the tasks a quantum radar needs compute won't be too complicated for a classical computer, so a classical computer will likely be the best for your circumstances.
How to optimize beam splitters?
"Beam splitters do not need to be optimized for your case, 50/50 beam splitters should work perfectly fine for the purposes of quantum sensing and detecting stealth aircraft."
Are there any other avenues or things we should consider or look into that may apply?
You should look into gravitational lensing and quantum astrometry for different avenues to pursue.
What are the benefits/potential applications of the work you did specifically with single-modes?
Some of the benefits and potential applications of the work included an easier manipulation of Qubits. In classical computing, legal moves are limited by a limited ability to perform tests. Quantum computing is a very similar set up, but with the ability to make unlimited moves. It will be best to keep the model of our radar simple, and not try to incorporate harder aspects such as single-modes.
Your article talks about the goal of finding a quantitative relation between the two properties of entanglement and superposition. How long do you think it’ll take to do that, and what would be the applications of that?
You can use superposition (one particle in two states) and entanglement (two particles in one state) to quantify the two properties in order to define NCP/CP
We are currently working to make a quantum radar that can hopefully detect stealth aircraft, or objects that might be harder for classical radars to detect. Could you talk a little bit about the applications of quantum radar in this field and also other applications of quantum sensing
"Quantum radars are still a new emerging technology and thus they aren't being used in military fields just yet. However, one application of quantum sensing is astronmetry. Quantum radars are already being used in Astrometry, using interferometric techniques to study the sky to measure objects in the galaxy. It works by having photons coming to you from stars, learning things not accessible from classical telescopes. This can be a good avenue of pursuit if aircraft detection gets too difficult."
The atmosphere is an incredibly noisy space. We are trying to account for it by using the two concurrent systems and also having some kind of noise tolerance on the computer side of the radar. Are there any other good ways to reduce error for the radar or to minimize its impact? Is it better to try and build error resistance into the actual radar or to try and correct it on the computer side?
What are some things that error can impact?
Would it be better to try and focus on creating a less noisy environment for the radar, or making it work in a noisy environment?
Angle the beam towards the correct way, different beam splitter won't work
Universality - if you have access to a certain universal quantum gate set, you don't need a specific beam splitter
We saw on your research page that you have done research with squeezed state photons, could you talk a little bit about how they are applied in quantum sensing and if it could potentially be applied in our project?
Quantum squeezing can be applied to this project, but it's difficulty may prove inhibitory to getting an established product. Focus on what you can get set in stone before jumping into the technical solutions.
What are some problems with our current design?
If there is any slight variation or time dependent differential path length you will get an indication that something is present when it might not.
Atmospheric turbulence: really small temp variations in air that change the index in fact in a minute that range from size and moving and evolving.
Dashed lines will spread out and the waves will be large.
What are some possible ways to work around those problems?
How high you want to choose the satellite to be
How big the optics are
If you take the products of the area of the area of the receive and wavelength and path length (add more math), you can form an image of the object
You can find atmospheric effects and light you are sending out
Be greater than one to get a single photos in the atmosphere
How will the weather affect it?
Light with changing weather-> issue with coherence
BUT amount of light is getting through varies
You do want a beam
Single photon system might not be working
Do you have any advice on selecting a wavelength?
AVOID Absorption lines
Differential absorption lidar
Scattering gets worse with shorter wavelengths
Blue is preferentially scared then longer wavelengths
Probably want it at a shorter wavelength
How should we set up the systems?
Computer Could work
What would not work:
Start as a sequence of single photos and vacuum propagations
Differentiation calculation to get to another end
Well what happens when I having something is the phase of the wave changes
How much phase gives you what kinds at the under end
Probabilistic
Filtering (background light)
Diffraction efficiently
Background light
Phase shift
Differential attenuation
Turbulence: Computer Simulation is very computation defensive
Would it be a problem if there were overlapping sets of beams?
No as long as the wavelengths are different and they would just go right through each other
What would be the best detector to use?
Superconducting nano wires single photon detectors: Fast with count rates in the millions
What is the best type of laser or wavelength of light to use?
AVOID Absorption lines
Differential absorption LiDAR
Scattering gets worse with shorter wavelengths
Blue is preferentially scared then longer wavelengths
Probably want it at a shorter wavelength
What methods of error detection have you used?
Background light -> need to filter the narrow pulse in time
A specific wavelength in retrospect for turbulence
Does the atmosphere have a large impact on the readings?
Light with changing weather-> issue with coherence
BUT amount of light is getting through varies
You do want a beam
Single photon system might not be working
What is the best way to ensure that the photons reach the final beam splitter at exactly the same time, to make sure they combine with the correct wave? Is there a distance at which they could become off?
How high you want to choose the satellite to be
How big the optics are
If you take the products of the area of the area of the receive and wavelength and path length (add more math), you can form an image of the object
You can find atmospheric effects and light you are sending out
Be greater than one to get a single photons in the atmosphere
We have been researching current designs of Quantum Radar, but we have had trouble finding a lot of specifics on how the current ones work. Could you please explain a bit about how they work and what other kinds of Quantum radar are currently in use?
I’m attaching a review paper I just found online that does a decent job of describing the current state of the art. You can find specifics about the different designs/experiments in there, as well as in all the papers that are cited in this review.
Please note that quantum radar and quantum LIDAR are basically the same thing, the only difference is the frequency/wavelength of the radiation used (radio frequency for radar, roughly optical or infrared light for LIDAR.) It’s currently generally easier to generate entangled photons in the optical part of the spectrum, so you might have more luck looking for quantum LIDAR experiments. In both cases the term is somewhat vague, and refers to the use of "non-classical" (synonymous with “entangled,” or “quantum") states of electromagnetic radiation to enhance the sensitivity or performance of a sensor that is trying to use that radiation to detect/map out objects. There are a few potential advantages of using quantum states of light:
1) You can gain more sensitivity or spatial resolution for the same number of photons/amount of radiation
2) You can design your sensor in a way that the signals you detect are harder to “spoof" or “cloak" than with the classical versions of radar/LIDAR
3) Because you can enhance your sensitivity for the same number of photons, you can in principle use it to detect objects while making it harder for anyone else to know you’re looking
What are some current struggles in the field of Quantum Radar?
The biggest challenge is that it’s pretty hard to generate non-classical states of electromagnetic radiation, and if you do they tend to be sensitive to things like photon loss, which occur naturally when you send radiation out and then try to detect it when it bounces back. In addition, in general these approaches really only help when you’re working with very low light levels (see the points above) and that makes it very hard to achieve the necessary signal to noise ratios to be useful, or to compete with classical radar and LIDAR using much higher intensities of radiation.
What are some of the current applications of Quantum Radar?
To my knowledge there really aren’t any. This is a nascent quantum technology that doesn’t really exist in the real world yet. Potential applications would probably mostly be focused on national defense, since the main advantages are that you can potentially detect objects without an adversary knowing, and/or you can be confident that an adversary isn’t tricking you into thinking an object is there when it isn’t, or isn’t there when it is. However, there are very related concepts within the broader field of "quantum imaging” or “quantum illumination” with potential applications to biology and medicine, where you want to image inside of cells or living organisms, and using light that is too intense will damage the organism.
"Till date, no advancement has been made against quantum radar because of its technology and LIDAR because of its higher accuracy and weather independence. As above all methods of reducing RCS have been cracked. The stealth technology has gone as far as it could go. The fact that a stealth technology aircraft like F-117 could be downed by a Third World country (Serbia) by upgrading its 1960 SAM system, proves the fact that all stealth aircraft are vulnerable to existing and futuristic counter-stealth technologies, " (Stealth Technology And Counter Stealth Radars: A Review)
"According to the signal detection theory, the relationship between plasma parameters and radar detection probability is built up through the SNR loss, in which the attenuation of radar echo and the mismatch loss of pulse compression are both considered. " (Evaluations of Plasma Stealth Effectiveness Based on the Probability of Radar Detection)
" Type 1: Non-classical quantum states of light are transmitted which are not entangled with the receiver. E.g., single-photon transmitters.
• Type 2: Classical (coherent) states are transmitted but quantum receivers are used to increase sensitivities.
• Type 3: Quantum states of light are transmitted which are initially entangled with the receiver. (Joint quantum measurements are correspondingly used.), "(Quantum Illumination and Quantum Radar: A Brief Overview).
"Here we demonstrate a superconducting circuit implementing a microwave quantum radar that can provide more than 20% better performance than any possible classical radar. "(Quantum advantage in microwave quantum radar).
"Quantum radar and quantum LiDAR, as quantum technologies, hold the promise of making a substantial impact on radar and scanning applications," (Advances in quantum radar and quantum LiDAR)
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