# Quantum Information Science and Technology

** - Overview**

Quantum information science and technology (QIST) is a multidisciplinary field that studies how quantum mechanics can be used to acquire, transmit, and process information. It combines quantum mechanics with computer science and information theory to develop theories, algorithms, and technologies that can surpass the limits of classical computation.

QIST covers both theoretical and experimental aspects of quantum physics. It draws on the disciplines of physical science, mathematics, computer science, and engineering.

QIST technologies can be divided into three application areas:

- Sensing and metrology
- Communications
- Computing and simulation

QIST is expected to play a large role in the economy and national security. Quantum technology can eliminate vulnerabilities to global navigation satellite systems and ensure zero drift. This means it can locate and navigate vehicles with pinpoint accuracy in any environment.

**- Quantum Mechanics**

Quantum mechanics is a physical science dealing with the behaviour of matter and energy on the scale of atoms and subatomic particles/waves. It also forms the basis for the contemporary understanding of how very large objects such as stars and galaxies, and cosmological events such as the Big Bang, can be analyzed and explained.

Quantum mechanics is the foundation of several related disciplines including nanotechnology, condensed matter physics, quantum chemistry, structural biology, particle physics, and electronics.

Quantum mechanics explains how extremely small objects can simultaneously have the characteristics of both particles and waves. Physicists call this the “wave-particle duality”.

Quantum mechanics was developed during the first half of the 20th century. The results of quantum mechanics are often extremely strange and counterintuitive.

Quantum mechanics requires a lot of math, including differential equations, path integrals, and matrix manipulation. Basic courses in mathematics that you should complete in order to understand quantum mechanics should include calculus and linear algebra.

One of the oldest and most common types of quantum mechanics is the "transformation theory" proposed by Paul Dirac. This theory unifies and generalizes the two earliest formulations of quantum mechanics: matrix mechanics and wave mechanics.

**- Quantum and Quantum Science**

A quantum is the smallest possible unit of anything, and Quantum Science is the study of these particles and their application. In other words, we know that all matter is made of atoms, but what is the smallest component of an atom and how does it react to stimuli? That deceptively simple explanation is an introduction to a field of science that is exploding into the disciplines of engineering and technology.

How and why did this science begin? According to the website Whatis.techtarget.com the science had its beginnings at the turn of the twentieth century with the research of a physicist named Max Planck.

Doctor Planck reasoned that since all matter is made up of individual units, energy might be as well. His research explored why glowing objects changed from red to orange and finally to blue as their heat increased. The behavior could be explained if the radiant energy existed as individual units instead of as rays, which was the conventional thought at the time.

From that point, scientists began to look at these small particles and their behavior, eventually using the research in the miniaturization of circuitry on microchips.

The problem in computer science is that this miniaturization is required for computers to process data. With the deluge of new information that must be catalogued and processed securely as well as the requirements that new scientific discoveries place on computers, the machines will soon reach their limits. That is what is driving the new interest in the quantum.

**- **Bridging Quantum Physics and Engineering

The theory of quantum physics has led many to wonder about the nature of matter. Quantum particles seem to react at times like individual particles and at times like continuous waves. This results in some surprising properties.

One of these, superposition, is the ability of quantum systems to include all possible measurements, and only take on certain characteristics when they are measured.

Entanglement is another property of the particles in which the characteristics of multiple particle systems correlate to one another. When you alter one set of measurements, the entire system changes.

At the point where these discoveries intersect known developments in information technologies, new opportunities burst open in computing, navigation, sensing, the ability to do simulations and in other areas. This is a rapidly-morphing science that is changing other disciplines as it grows.

All of this can seem “other-worldly,” but the principles are already at use in our own world. The atomic clock was invented using quantum principles. That involves more than making certain people arrive at appointments; the world’s stock markets and GPS systems rely on accurate time reckoning.

According to an article in smithsonianmag.com, quantum principles are the foundation of “quantum cryptography,” or sending messages through a quantum channel which makes them virtually undecipherable to anyone without the quantum “key.” The concepts also are resulting in super-fast computers.

Many of the technologies we take for granted today rely on mathematical formulas and equations. As the technology advances, these equations will get more complex. Current computers could take literally “forever” to process them. Theoretically, quantum computers could solve them in seconds.

That word “theoretically” is the crux of the science. A lot of what research and theory hint at is still only conjecture. There is much left to discover and so many applications to the research that they would create a new world.

There are issues of ethics and practicality that complicate the field of Quantum Science and yet the future to the science is a door that cannot be closed now that it is open.

**- Quantum Information Science**

Quantum physics has already changed our lives. Thanks to the invention of the laser and the transistor - both products of quantum theory - almost every electronic device we use today is an example of quantum physics in action. We may now be on the brink of a second quantum revolution as we attempt to harness even more of the power of the quantum world.

Quantum computing and quantum communication could impact many sectors, including healthcare, energy, finance, security, and entertainment. Recent studies predict a multibillion-dollar quantum industry by 2030. However, significant practical challenges need to be overcome before this level of large-scale impact is achievable.

Quantum information science is an area of study about information science related to quantum effects in physics. It includes theoretical issues in computational models as well as more experimental topics in quantum physics including what can and cannot be done with quantum information.

The term quantum information theory is also used, but it fails to encompass experimental research in the area and can be confused with a subfield of quantum information science that studies the processing of quantum information.

**- Quantum Algorithms**

Quantum algorithms are step-by-step procedures that can be performed on a quantum computer to solve problems. They can be used to solve a wide range of scientific and industrial problems, including simulating chemistry and physics, optimization, and machine learning.

Quantum algorithms differ from classical algorithms in that they work with qubits, while classical algorithms work with bits. Quantum algorithms can also take advantage of superposition and entanglement, which are not possible in classical computing.

Quantum algorithms can achieve a speedup or other efficiency improvement over any possible classical algorithm. Some applications of quantum computing include breaking cryptographic systems and designing new medicines.

**- Shor's Algorithm**

In the last two decades of the previous century more and more quantum mechanical concepts were brought into information processing, allowing the development of so-called quantum algorithms.

One of the early breakthroughs and still one of the strongest arguments for quantum computing to date is Shor’s algorithm for integer factorization into primes. In many ways this algorithm can be seen as a starting signal. Since then the efforts in learning about what is required to build a quantum computer increased manifold.

Shor's Algorithm, named after mathematician Peter Shor, is a quantum algorithm designed to efficiently factorize large composite numbers. It's one of the most famous and impactful algorithms in quantum computing, as it provides an exponential speedup over the best-known classical algorithms for factoring.

**[More to come ...]**