Objective:

We aim to reveal the information we can learn about retina from high-precision optical measurements (quantum metrology) by stimulating the human eye with quantum light (photons); to evaluate the advantages of quantum states relative to each other and classical ones; and to pioneer quantum biometry, quantum ophthalmology, and quantum psychophysical research under the light of these information.

Novelty:

Following Planck’s unveiling the quantum nature of light, researchers question the minimum number of photons that the human eye could perceive. The experiments conducted in the early 1940s revealed that we could see a few photos. Recently, with the development of single-photon sources, more sensitive experiments, which use the human eye as photon detector, have been proposed. Such analyses, in conjunction with quantum optics and quantum information, can test the foundations of quantum mechanics. They can illuminate quantum entanglement, superposition, and wave-particle duality. The novel questions this project raises are:

1. What information can we extract from the vision system using photonic quantum metrology?
2. What are the advantages of quantum measurements and quantum states over each other or classical systems?
3. Can we suggest secure biometry, high precision diagnosis of vision or neural disorders with quantum technologies?

We will also illuminate the controversial issues of if the perception of photon can happen at the brain; or if human eye could classify entangled states. We will develop an innovative approach that will handle the neural network structure of the visual system, together with the photodetector model of the eye. The current literature is developing in two different directions. The research on the tests of quantum mechanics takes the eye as a photodetector. The neural network structure of the visual system has a different literature. Our study will be a pioneer in the synthesis of neurology and quantum metrology.

Method:

In preliminary studies, we used an elementary neural network model of the retina consisting of two photoreceptors and a ganglion cell. We considered photons in: (i) Coherent and (ii) Fock states. Within the parameter estimation theory, we calculated the Fisher information and the Cramér-Rao bound. Our results showed that photons in Fock states, which has higher quantum character, can probe the synaptic links more precisely. These promising results reinforce the hypothesis and motivation of our project. We will further consider quantum noise reduced (squeezed) light; analyze the high-sensitivity advantages of entangled photons by proposing quantum interferometry schemes using both eyes. We will use machine learning network methods based on the similarity of retina neural networks and learning networks, for large-scale retina models with different cells and layers. These methods will be used for quantum biometric, quantum ophthalmic devices, and experimental proposals. We will combine psychophysical methods, neuroimaging methods, and photonic metrology to for novel brain and mind function analysis.

Contributions:

Fundamentally, our project will give significant information on neural network models of the visual system, on differences between photodetector perception and “seeing” a photon, on wave function collapse in the human eye, and on the interaction between quantum light and eye. We will pioneer synthesizing neurology and quantum metrology. Practically, we will propose high-precision quantum metrology schemes for the diagnosis of neural system disorders with increased reliability and novel biometric devices with enhanced security. Detailed retina models to be developed in our project will provide valuable information for retinal implants, mind/eye-machine interfaces. Results of our project will have high patent potential.