Why Quantum Computing?

We know that Quantum Computation depends on the quantum mechanics which is a mathematical model that defines the evolution of physical realization of computation and hence the quantum computer itself. Up to now several physically equivalent formulations have been found for quantum mechanics.

Quantum mechanics defines the behavior and internal properties of elementary particles such as electrons or photons on the atomic and subatomic levels. In the first half of the 20th century many scientists formulated, including Schrondinger, Bohr, Heisenberg and Dirac, in the late 70’s quantum information processing systems has been proposed. Even later, in the 80’s of the last century Feynman suggested the first physical realization of a Quantum Computer. Benioff also was one of the first researchers to formulate the principles of quantum computing and Deutsch proposed the first Quantum Algorithm. Due to Moore's law there is now rapidly increasing the interest on these topics in computer engineering community. That is: the number of transistors in a chip doubles every 18 months and the size of gates is constantly shrinking.

Electronic devices issues like heat dissipation and information loss are becoming very important for current and future technologies. Improving the scale of transistors ultimately leads to a technology working on the level of elementary particles, such as a single electron or photon. Since Moore’s paper the progress led to the current nano circuit technology which considering the size of an approximately 10−10m . Consequently the exploration and its related Quantum Computing becomes very important to the development of future devices and in consequence to the development of quantum algorithms and quantum logic and architecture techniques which will change the dimesions of future computing.

Current progress in implementation and architectures prove that this area is just at its begining and is gorwing. For instance the implementation of small quantum logic operations with trapped ions are the indication that this time-frame of close future can be potentially reduced to only a few years before the first operational quantum computer is developed. Currently, most recent implementation of quantum computer is the adiabatic computer by D-Wave Systems. Although up to now it is still an open issue whether the DWAVE computer is a proper quantum computer or not, it provides considerable speed up over classical computer in the (RNG) Random Number Generation. Even in presence of adiabatic quantum computer, architectures for full quantum computers have been proposed.

In these suggestions the quantum computations is implemented over a collection of photons that represents the degree of freedom between qubits. Such architectures have not beenBecause of their super performance and specific problem solution power, quantum computers will be predominantly used in computational intelligence and robotics, and similarly to classical computers they will ultimately enter every area of technology to boost computing power. Despite the fact of being based on paradoxical principles, Quantum mechanics has found applications in almost all fields of scientific research and technology. Although only theoretical concepts of implementation of complete quantum computer architectures have been proposed the continuous progresses in technology will allow the construction of Quantum Computers in close future, definitly in coming 10 to 30 years.

What Do We Expect From Quantum Computing?

The question is how long does it take to develope fully operational quantum computer. Commonly know as Quantum Supremacy. The goal is to build a system, that can performs maximum calculation and manipulate most of the qubits. Number of qubits in quantum technology is increasing day by day. Quantum computing and Quantum Information Science holds great promise for solving most important and complex classically intractable computational problems. Currently, ongoing work in theoretical and experimental physics continues to make new advances in a number of technologies that might one day underlay a quantum information processor which will be used to boost quantum computing. Relatively little investment has been made in exploring the computer science side of quantum information science even though the challenges that quantum computing poses to the world of computer science are on a par with the challenges posed to the world of physics.

Intelligence Advanced Research Projects Activity Quantum Computer Science Program explores questions relating to the computational resources required to run quantum algorithms on realistic quantum computers. Any implementation of a quantum algorithm requires not only programming the algorithm at a logical level but also the incorporation of error correction and control schemes at the physical level, and resource estimation must account for all of these factors.

The QCS program is developing a tool chain to study these issues throughout the computing process.The tools will include an integrated development environment for the quantum programming languages already developed by the program, compilers to generate logical circuits, and tools for analyzing quantum error correction and control protocols. Through its research QCS will build a foundation for measuring and reducing the resources required to program and implement complex quantum algorithms of realistic size.

Quantum computers are in theory capable of simulating the interactions of molecules at a level of detail far beyond the capabilities of even the largest supercomputers today. Such simulations could revolutionize chemistry, biology and materials science, but the development of quantum computers has been limited by the ability to increase the number of quantum bits, or qubits, that encode, store and access large amounts of data.

In a paper published in the Journal of Applied Physics, a team of researchers at the Georgia Tech Research Institute and Honeywell International have demonstrated a new device that allows more electrodes to be placed on a chip an important step that could help increase qubit densities and bring us one step closer to a quantum computer that can simulate molecules or perform other algorithms of interest.

This work was funded by the Intelligence Advanced Research Projects Activity. As Quantum computer is able to perform most complex calculations quantum computers are capable to break any encryption system we are now using today, which is a big threat to the modern communication system. Simply defined in Shor's Algorithm. Despite that, quantum computers require quantum communication to be operated on global level.

IBM MAY 4 QUANTUM CHALLENGE 2020

On May 4 on the occasion of IBM Quantum Experience’s 4th anniversary, IBM announced a Quantum Challenge 2020 which consists of a four-day challenge in which participants were asked to solve four exercises that were designed in the way of increasing complexity in order to secure an IBM Advanced Quantum Badge.

These exercises were a great source of learning, made us utilize our previous knowledge, and have further research on the topics we knew before. Brief descriptions about each exercise are given below:-

Exercise 1:-

The first exercise of the challenge included quantum gates and quantum circuit design. There were two parts in this exercise, first part consisted of single-qubit circuits and the second part consisted of double qubit circuits.

In the first part, the first question here included a bit flip in which we were supposed to reach quantum state 1 from quantum state 0.
Other questions included superposition in which we were supposed to design a circuit, changed the value of quantum bit from one state to another.
We design some quantum circuits and the code also showed up, we simply copied that python code and paste it in the respective cell and ran it.
In the second section we were asked to construct circuits for bell state, another question was asked to swap the state of the first and second qubit, continuing with another question that includes the construction of GHZ state on three qubits, we were supposed to run it with 2000 shots.
After this, we ran the submission cell of exercise 1 and my all answers were correct so it was a successful submission.

Exercise 2:-

Errors are part of every measurement. In Quantum Circuits we experience noisy results with errors most often. These errors must have to be reduced for better results.
Our second exercise was based on Measurement Error Mitigation.

This exercise consisted of four multiple-choice questions in which we had to choose error-free counts of the same circuit as given in the respective questions. After running all the cells successfully, we ran the submit cell and it got submitted successfully.

Exercise 3:-

It was the most interesting exercise of the challenge because it was Quantum Cryptography. In this exercise we had to work on BB84 protocol, do not get confused with the name as it is based on the initials of its inventor Bennett and Brassard and 84 here means it was invented in 1984.

At first, there was some brief introduction of the protocol, given there was a chart regarding the protocol as well as an illustrated example that helped in understanding the protocol.

In this protocol, there are two individuals named Alice and Bob whose work is to send and receive messages respectively. The challenge in this exercise is that we were supposed to play the role of Bob, along with Alice we were supposed to make an encrypted key, and then used that key to decrypt the message.

The first question here included programming to get bitstring, the second one included extracting the key using BB84 protocol. The third question included decrypting the message using the key that we just fond earlier. Wait, the exercise has not finished yet, the answer we got was in Morse code and we were supposed to decrypt it again in normal language. We got it correct and the final decrypted message was a link of Geddit in which there is a hint that something we found in exercise 1.

Finally, after submitting the exercise we were now supposed to do the most challenging and difficult exercise of the challenge of the exercise.

Exercise 4:-

It was the last and the most challenging exercise of the challenge. We had to play with circuit decomposition. There is a line on the website, it quotes “The fourth problem is supposed to puzzle even the quantum experts among you, so don’t worry if you cannot solve it. If you can, hats off to you!”. By reading this line you can understand the complexity of this exercise.

In this exercise, we were supposed to decompose our circuit in the form of Control Not (CX) and U3 gate, and this exercise will be accepted if we get our cost smaller than 1600. Here, cost means the number of cx and u3 gates altogether with a different number of costs for each.

Finally, after a lot of research and a lot of hard work, we managed to reduce the cost below 200 and our exercise got submitted.

You must be wondering what is the hint we got in exercise 1, so here is the revelation, the answer code we get on exercise 1, after decrypting it. We find out that it says use Hadamard Gate (H). We use the hint and Alhamdulillah solved it.

So, here is the short story about our experience in IBM May 4 Quantum Challenge 2020. After a few days, I received my IBM Advanced Quantum Badge which is shown below and this increases my motivation towards studying Quantum Computing. I am looking forward to more such exercises and following is my GitHub repository link in which you can check the solution of the exercises.

Click here to view my GitHub repository for the solution to the challenge.