Introduction

Written by Angshita Mandal, Yashashwani Garg

Quantum computers, quantum processors, quantum this, quantum that, is and have been all the buzz for quite some time now. Even the Nobel Prize in Physics for 2022, was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger for their work in quantum mechanics. But why does the scientific community even bother studying this; why Quantum?

To answer this, let us delve into how quantum physics came into being. It all started with the breakdown of the classical assumption that matter exists as either particles or waves but does not show properties of both. This view came into question in the 1900s during work conducted on heat radiation by Otto Lummer and Ernst Pringsheim. This led to the formulation of what is called the ‘Black body radiation’ and Max Planck’s assumption of discrete energy values (integral multiples of: h ). Einstein’s Photoelectric effect, De Broglie’s matter waves, Schrodinger’s wave equation, Bohr’s atom and atomic spectra and many others led to the development of modern quantum physics that has wide-reaching implications today.

Quantum Entanglement is one of the fundamental features of quantum physics and has befuddled scientists for nearly a century. The Einstein-Podolsky-Rosen Paradox, questioning the quantum theory, and Bell’s counter have aided in understanding this ‘spooky action-at-a-distance’ (in Einstein’s terms) phenomenon of Quantum Entanglement.

But what does this phenomenon have to offer, and how is it important for us? Quantum entanglement, central to the work of the 2022 Nobel Laureates in Physics, has created a vastly different and secure way of information processing; Quantum information science offers ways to transmit data through quantum key cryptography securely, process information via qubits and so much more. Quantum computers are the new in as classical computers slowly lose their previous bling.

CLASSICAL COMPUTING? NAH, I’D RATHER GO QUANTUM

So, what exactly is a Quantum computer? Is it just some fancy name given to a rather simple device just to garner attention or is it something of great value? I’d say it’s the latter option. Quantum computers, though not fully understood, stand to ease the burden of complicated calculations, and provide a secure network for data exchange.

Quantum computers work on qubits instead of the good ol’ classical bits representing the on (1) and off (0) states. Any quantum system that can exist in two distinct basis states is called a quantum bit or a qubit. Now, these quantum bits can exist in the on and off states simultaneously, owing to their property of Superposition - the ability of a system or an entity to exist in multiple forms at the same time. This helps qubits carry more bits of information compared to the classical bits in which one state corresponds to exactly one bit of information, n qubits will carry information equivalent to 2^n classical bits, that’s quite a boost in data storage and processing.

We have mentioned data processing quite a few times now, so who or what exactly processes this data in a quantum computer? To do this tedious job, we have quantum processors in which each particle is subjected to the principle of juxtaposition and this principle allows it to overcome the on-off combination and thus increase calculation capacity or the amount of information conveyed. These processors work based on certain feasible quantum algorithms, making our work easier and faster. Although managing a Quantum processor is not yet optimal, Superconducting Quantum Processors, advanced Quantum-Classical Orchestration, etc. push the quantum computing speed and capacity needed to change the world.

QUANTUM COMMUNICATION- THEORY TO PRACTICE/ BUILDING A QUANTUM COMMUNICATION NETWORK

Now that we know what goes into the working of a quantum computer, let’s look at quantum communication and its key components required to develop a sturdy quantum network.

Quantum Communication helps in developing quantum devices and its goal is to bridge the gap between fundamental quantum mechanics and their given application in information technology. So, what goes into making an efficient quantum communication system? We have a multitude of devices and processes at work, of which, some of the most important ones are:

Quantum interface in which a photon or a light particle can cross its own trajectory path followed by interference with the direction of its path, it also helps in detecting different quantum computing technology and long-distance transmission.
In a Quantum Memory scheme, light particles arriving at a Bell state measurement device interfere. Here, single photon particles arrive at the exact same point at the exact same time on a beam combiner. And to give it a possible outcome, Quantum Memory can be used to store the quantum property of each photon until they are all available and then release them onto the beam combiner for interference.
Single-photon sources produce one or fewer photons in a given timeframe. Single photons are very useful for studying quantum phenomena and serve as efficient qubits. They generate photons of the same wavelength that are indistinguishable from one another. These sources can be Deterministic or Probabilistic (produce photons in pairs).
Single-photon detectors serve as devices to detect the presence of a single photon. They offer required support for quantum information applications such as timing jitter, latency and max count rate among others.

MOVING ON…

Here, we have touched upon the very basics of quantum computation, but this is not all. Quantum entanglement, a state in which two separate particles are connected without being in contact with each other, is one of the most crucial and perplexing aspects in the development of quantum computation technology; John Stewart Bell, a physicist from Northern Ireland, forayed into the world of quantum mechanics, formulating Bell Theorem that provides insight into the local hidden variables theory and quantum entanglement, shedding light on topics that have eluded scientists for years.

This is just the tip of the iceberg, to learn about Bell's theorem and Bell’s inequalities, stay tuned for our next post for it is sure to satisfy your curiosity.

Page updated

Report abuse