Dec 3, 2021

5 min read

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Any technology enthusiast must have heard about **Quantum Computing** by now since it has caused a massive upheaval in the technological area and has had a significant influence on numerous industries. For those who are unfamiliar with quantum computing, it is a branch of computing that creates technologies based on the concepts of quantum theory. **Quantum theory** is a fascinating field of study and research because it deals with the behaviour and energy of materials at the atomic and subatomic levels. Incorporating quantum physics into computing has resulted in one of the most exciting disciplines of research to date.

A **quantum network** is an essential and powerful tool of quantum computing, as it connects with quantum data stored in the form of individual photons. Quantum networks, by utilizing the intrinsic power of quantum states, might allow innovative approaches such as: physics-based unhackable security, more powerful quantum computers that can accomplish jobs that would normally take years, and networks of entangled quantum sensors.

The idea of **quantum entanglement** emerges from this. The initial function of a quantum network is to spread entanglement, but first, we must define the term. As we all know, 'bits' hold classical or non-quantum data. **Qubits** are a comparable probabilistic quantity of quantum data. When two qubits connect, their probability distributions interweave, and they become reliant on one another—this aids in comprehending the measurement of one qubit by examining another in the relationship. Entanglement refers to this type of relationship or association, and a quantum network is used to distribute entanglement across the globe through different processes.

But what is the objective behind this distribution? Entanglement gives the users the advantage of using the correlations to innovate new applications that were otherwise not possible with classical data, thus allowing global Entanglement as a Service (EaaS).

EaaS, or Entanglement as a Service, is a cutting-edge technology that connects users of quantum networks with entangled qubits (quantum bits) over vast distances via quantum repeater networks. Quantum networks will enable new services, ranging from ultra-secure communication to high-performance computing (HPC). We will talk about quantum repeaters in a bit.

EaaS is completely dependent on the internet, and even though it works on a simple concept, it might be a little hard for the users to grasp. To understand EaaS better, let us look at the process behind any applications of the internet. The internet's core service is just transmitting data from point A to point B. Because the internet allows computers to connect with one another, data is transferred in the form of bits. The internet has divided communications into packets that are made up of bits. Packet switching enables the internet to handle huge amounts of data.

So, what is the process that the quantum internet follows to provide its fundamental service? As discussed earlier, quantum entanglement provides correlations between qubits that can be used for many purposes. For basic communication, teleportation or transportation of qubits can be done. In addition, entanglement can be used for applications that are not possible through today's internet. Quantum networks can use entanglement to enable an encrypted connection in which information is conveyed using entangled qubits without ever needing to transmit it over a potentially hazardous network. Furthermore, entanglement may be used to build even bigger quantum computers via distributed quantum computing.

A quantum networking company called Aliro Quantum is advancing its efforts to develop quantum EaaS. As Jim Ricotta, the CEO of Aliro, said,

**" If you entangle two photons and someone makes a change to photon A, another person can observe that change at photon B, because they've been entangled; it's the law of physics. But it's invisible to the naked eye."**

Quantum networks work by entangling photons with data, which may then be encoded and sent through the same ground-based telecom fibre that is already in use. Entanglement enables the safe transportation of qubits, which carry quantum information. Thousands of such entangled photon pairs must be produced each second in order to yield significant information. The bandwidth of these connected photons is comparable to that of a regular network. We are still in the early stages of quantum computing, and in the future, unfathomable applications will be created on quantum networks.

In the above discussion of EaaS, there have been many mentions of Quantum Internet. The quantum internet is a network that will allow quantum devices to exchange data in an environment that uses the strange principles of quantum physics. In principle, this would provide the quantum internet with new powers that are currently difficult to achieve with web apps. Qubits may be transmitted over a network of physically isolated quantum devices with the assistance of quantum internet.

This all might seem similar to standard internet; then why do we need quantum internet? Transmitting qubits over a quantum channel rather than a conventional one basically implies exploiting particle behaviour at its lowest scale — so-called "quantum states." Interestingly, qubits cannot be utilized to convey data that we are accustomed to, such as emails and WhatsApp messages. However, qubits' unusual nature is opening up tremendous potential in other, more specialized applications.

Now that we grasp the significance of quantum internet in sending quantum data over great distances, we must learn about quantum repeaters, which serve as the key to unlocking the services of the quantum internet. The work of the standard repeaters is to measure the signal coming in from one side, copy it, and retransmit it to the other side at a greater power level. As a result, the quantum internet can safely transport data across very vast distances. But this cannot be done for quantum information, as quantum information cannot be copied due to the no-cloning theorem.

We cannot evaluate quantum states as they travel from point A to point B without destroying them. Although this gives some of the incredible benefits of quantum communications, such as ultra-secure communication, it also implies that we can't utilize the same notion from conventional repeaters to avoid loss in quantum channels. To avoid this loss, we use quantum repeaters.

To deal with the problem of loss, quantum repeaters employ a totally different technique than conventional repeaters. The central concept is based on the entanglement switching approach. The fundamental objective of quantum networks is to disperse entanglement across network members. Entanglement distribution enables a wide range of applications, including the transmission of qubits. Entanglement switching is a smart solution to the problem of loss that does not violate the no-cloning theorem.

Although there are currently no commercially manufactured quantum computers, quantum computing is widely utilized since it is far more powerful than normal computing and is employed by large corporations such as IBM, Rigetti, Toshiba, IonQ, and many more for Big Data analysis or simulations. Although complicated, quantum computing is extremely safe for transactions and many times quicker than conventional computation. At the 2019 IBM Summit, Google's quantum computer, Sycamore, did a computation that was 158 times quicker than the world's fastest computer. However, quantum computers are extremely costly to create and are not available to everyone. Hopefully, as the field advances, it will be freely accessible to individuals at a fraction of the present cost.