No one is quite sure who is behind the invention of the telescope. However, it is known that in 1608 Dutch eyepiece maker Hans Lipperhey announced a new vision instrument based on lenses. The invention made distant objects appear much closer. Since then, work on improving the telescope has evolved and become crucial to changing perceptions of the universe around us. Telescopes are not just reserved for scientists – they have been popular tools for observing the Moon for centuries. Sir Lower, made a number of observations of the Moon using a telescope provided by Harriot. He noted that the lunar surface looked irregularly like a tart that my cooke made me last weeke [1]. How developed is space research today? What does Poland have to do with the application of quantum-assisted telescopes?
Very Long Baseline Interferometry
The Very Long Baseline Interferometry (VLBI) technique is an advanced observational method that relies on combining data from multiple telescopes located at distant sites. This allows a very high angular resolution to be achieved, which allows the precise study of the chemical composition and physical properties of astronomical objects such as galaxies, star clusters, and planetary systems.
In the VLBI technique, the light emitted by an object is collected by at least two telescopes and then brought to a single location where it is interfered. The VLBI capability to generate highly accurate images and spectral charts of celestial entities could not be achieved using a lone telescope.
A revolutionary VLBI scheme was proposed in 2012. Daniel Gottesman and his team proposed using quantum entangled particles to aid the VLBI technique. Quantum entanglement is a phenomenon in which two particles are so strongly connected that a measurement of one particle immediately affects the other, regardless of the distance between them. In this way, the particles can be used as information carriers that transmit information about photons collected by telescopes in a much more efficient way than traditional techniques. [3]
What is the Quantum-Enhanced Telescopy?
Quantum-enhanced telescopy aims to use the methods known from quantum mechanics to improve the performance of telescopes. Quantum mechanics is a branch of physics that describes the behavior of very small particles (such as atoms and molecules, in a particularly precise way). The use of these principles in telescopes makes it possible to obtain higher-quality images of cosmic objects that emit a small amount of light toward Earth. The use of photon detection systems or aberration correction in such telescopes allows telescopes to increase sensitivity and resolution.
The Quantum-Enhanced Telescopy project is a collaboration of experimental and theoretical groups from a number of institutions (including University of Rochester, Chapman University, University of Illinois w Urbana-Champaign). About $2,000,000 has been allocated for its development (NSF grant 193632). The scientific team involves Robert Czupryniak, Polish PhD student in Prof. Andrew Jordan’s Group.
The Polish Achievement
We approach the field of telescopy in a peculiar way. Instead of treating it in terms of optics, we consider it in the language of quantum information. We show that the techniques commonly in quantum computation can be used to examine the stars.
It happens to be a great approach when one looks at stars that send few photons towards the Earth. In such cases, the methods known from quantum mechanics are extremely beneficial.
However, there are seemingly trivial questions: has the stellar photon even arrived? When did it happen?
In case of multi-telescope techniques (e.g., VLBI) the solution appears to be trivial. Just use each telescope as a detector; it the detector clicks, the photon has arrived there. But it does not work! Such a method destroys the information that the photon carries about the structure of the star. We need something else.
Therefore we have two essential questions: How to show if and when the stellar photon has arrived? How to examine the structure of the star?
We introduce the Clock Game [2] – a task formulated in the framework of quantum information that can be used to improve the existing quantum-enhanced telescopy schemes. We show how to determine the stellar photon arrival time without destroying the information it carries about the structure of the star. Finally, we demonstrate how to efficiently use quantum entanglement to achieve that task.
The Clock Game is the first ever proposal of quantum-enhanced telescopy task that can be used as a subroutine in other stellar imaging schemes. We tell if and when the stellar photon has arrived, which tremendously simplifies the imaging task. However, we leave open the choice of method used to get the structure of the star. Moreover, thanks to our Clock Game subroutine, the latter task becomes significantly simpler.
Finally, our Clock Game can be used in tasks outside telescopy, since it is formulated in a more general framework of quantum information. However, that will require further studies – Robert Czupryniak (Prof. Andrew Jordan’s group, University of Rochester).
Scientific breakdown
A similar question of photon arrival time was examined in Mikhail Lukin’s group from Harvard University. However, the solution proposed is significantly different to the one coming from Andrew Jordan’s group. While Khabiboulline et al. [4] (Lukin’s group) assume a protocol based on qubits, Czupryniak et al. [2] do not. Is makes the latter solution more universal and applicable within a wider range of quantum
Quantum bits, also called qubits, are the basic units of information in quantum computers. A qubit can be represented by the quantum state of a two-level quantum system, such as electron spins or photons. Qubits can be manipulated using various quantum operations (e.g., rotations and controlled quantum gates), making it possible to process information in ways not possible with classical bits. Thus, if a technology that operates on qutrites, for example, emerges, the solution proposed by Czupryniak et al.is more efficient and universal than the one presented by Khabiboulline et al., as it can be applied on a wider range of experimental schemes.
Quantum information language – the future for the Polish economy?
The publication “Quantum telescopy clock games” is not written in the language of telescopes and optics but in the language of quantum information. This gives the possibility of potential applications in technology in other fields. With quantum information, it is possible to secure communications between government institutions, which are particularly vulnerable to cyber attacks. The second area, which is extremely important for the development of the Polish economy, is new technologies. Quantum information can help develop other new technologies, for example, quantum data transmission, which is more secure than traditional data transmission methods. Poland can become a leader in quantum technology research, which can attract foreign investment and skilled labor.
[1] Roche (2004). “Lower, Sir William (c.1570–1615)”. Oxford Dictionary of National Biography (online ed.), Oxford University Press, Published online: 23 September 2004
[2] Czupryniak, Chitambar, Steinmetz, and Jordan (2022), “Quantum telescopy clock games”, https://journals.aps.org/pra/abstract/10.1103/PhysRevA.106.032424
[3] Gottesman, Jennewein, and Croke (2012), “Longer-Baseline Telescopes Using Quantum Repeaters”. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.109.070503
[4] Khabiboulline, Borregaard, De Greve, and M. D. Lukin “Optical Interferometry with Quantum Networks” https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.070504
Zuzanna Czernicka
