# Taking a Quantum Leap – The Theory, The Mechanics and The Computing

The **atom** that makes up the *matter* and the **photons** that makeup the *light* at the microscopic level behave quite differently than the way matter behaves at the macro level. There is a peculiar disconnect, atom can exist in two different states simultaneously and at different places at the same time…the ultimate search is on by the scientists to discover that elusive disconnection at the microscopic level of matter that matters to us in our everyday life.

## It is that intriguing phenomena where the ordinary matter behaves in an extraordinary fashion…we are yet to fathom the mystery.

**Schrodinger’s Cat** is a thought experiment designed to point out a flaw in the Copenhagen interpretation of superimposition as it applies to Quantum Theory. *It is a fascinating paradox…*

### How can be the cat dead and alive simultaneously at the same time?

**What is Quantum?**

It is a *Latin* word for amount. In physics, quantum is the minimum amount of any physical entity involved in an interaction. A photon is a single quantity of light. It is the minimum amount for light.

**Quantum Theory**

We have observed the behavior of matter at a grand scale. The way planets behave in a galaxy. The way big things behave on planets. The behavior of matter in our planet is different from the matter in other planets. Inside the grand scheme of things that are visible and seen, there are so many granular things that keep happening. We have lesser knowledge at that microscopic level. The quantum theory explains the nature and behavior of matter at the atomic and sub-atomic level. The energy of the electron within an atom is quantized and exists only in certain discrete values. These are alternatively referred to as quantum physics to quantum mechanics.

To appreciate the aspects of Quantum Theory it is important to understand

Theory of Relativity. It was Einstein’s path breaking theory that changed the fundamental premise of Newtonian physics. This theory described the nature and captured the behavioral pattern of only the large objects around us.

**Quantum Mechanics**

Mechanics is a subject of physics. The subject matter of physics includes from mechanics to radiation to electricity to magnetism. It is a specialized area of physics dealing with the motion of bodies in a frame of reference. The action of forces affecting the material bodies. Hence quantum mechanics not necessarily denotes the same as the subject of mechanics. Quantum Mechanics is a body of scientific knowledge which deals with the behavioral aspects of electrons, protons, neutrons and other particles of matter that make up the universe.

**Quantum Computing**

It is the power of computing using quantum mechanical phenomena such as superimposition and entanglement. A quantum computer works with particles that can be in state of superimposition. A quantum computer is a device that performs quantum computing. It is different from binary digital electronic computers using transistors. Quantum Computing is an area of study focused on developing computer technology based on the principles of quantum theories.

*What is qubits?*

A **qubit** is shorter version of *quantum bit*. As bit can either be in on/off or true/false state i.e. the binary state of 0 or 1. A qubit can also take the value of 1 or 0 simultaneously. A single qubit comprises of an electron of a phosphorus atom inside a layer of silicon. A quantum computer processor would comprise of 100 qubits.

**Quantum Probability **

According to **Max Born**, the motion of particles follows probability laws. Quantum Theory is based on the principles of probabilities as measuring a quantum system do not produce the same outcome, and every time it produces one of many outcomes with certain probability. It does matters in which order we look at the observable of a quantum system.

**Light & Matter**

It is stated that light is a form of energy, not matter. The irony, energy and matter are different facets of same thing. Also, energy is produced from matter but has no mass. Matter and energy are completely interchangeable. It is established by the iconic equation of **e=mc^2**. Matter is made of atoms. Light is electromagnetic radiation. According to the first law of thermodynamics, the total amount of energy in a closed system will remain the same, it cannot be created nor destroyed.

It was the year **1905 Einstein** created the quantum theory of light, the theory stated that light exists in tiny particles called as photons. According to the Theory of Special Relativity, the laws of physics are same for all non-accelerating observers. The speed of light in a vacuum is independent of the motion of all observers.

If an object moves faster than the speed of light i.e. 186,000 miles per sec then the mass becomes infinite and so does the energy needed to move it. Hence no object can move faster than light. The current standing of the proposition that stands firm unless otherwise proved with any new hypothesis.

It is much the way when

Einsteinproposed a new hypothesis against the prevailingNewtonianphysics.

When a light interacts with matter, depending on the wavelength of light and the type of matter, light could be absorbed, transmitted or reflected. At atomic level it can either move the atom to the higher level or absorb the packet of energy. Matter absorbs light only when the photon’s energy matches with that of molecules. When light is absorbed by the matter, it increases the temperature. The** Photoelectric Effect** is an example of how matter absorbs light.

**Particle & Wave**

In Quantum Theory each particle acts both as a particle and also a wave. This is called as duality. A particle is a localized point in the space. At a given point of time only one particle will be present at that moment. Light is a particle and the flow of particle i.e. photon is what we call as wave. Light has a dual characteristics. In **1924, Louis de Broglie** stated that all microscopic material such as atoms, molecules to electrons and protons also have dual character much like light.

It is the De Broglie equation. In quantum physics it is state that particle can act both as a particle and a wave. Light is nothing a collection of photons propagating through space as electromagnetic waves. Both light and matter behave like a wave at large-scale and behave like particle at small-scale.

**Classical Mechanics **vs.** Quantum Mechanics**

Mechanics is a branch of physics that deals with the study of motion of material objects, it is about the process of how the action of force affects material bodies. ** Motion** is one of the most fundamental aspect in the subject of science. After the very idea of life is about motion and movement.

Quantum Mechanics is a branch of physics that deals with physical phenomena at the microscopic level. Classical Mechanics is a branch of physics that deals with the motion of bodies based on Newton’s law of mechanics.

In

Classical Mechanicsmatter can absorb energy in any amount. But according toQuantum Mechanicsmatter can absorb energy in specific increments.

**Erwin Schrodinger **

*Wave Mechanics*

Schrodinger came with the groundbreaking wave equation for electron movements. It was step ahead to the Bohr’s model where electron was treated as a particle moving in fixed orbits around the nucleus. In Schrodinger’s ** Mechanical Model**, electron is treated mathematically as a wave. It revolutionized quantum mechanics. It gives us the probability of finding a particle at a certain position. The wave function is now accepted to be a probability distribution.

**Werner Heisenberg**

*Matrix Mechanics*

Heisenberg developed new theories about quantum mechanics about the behavior of electrons. His famous ** “Uncertainty Principle”** explains the impossibility of where something is and how fast it is moving. The very act of observing alters the position of particle being observed. This makes it impossible to accurately predict its behavior. In turn it means that the position and velocity of a particle cannot both be measured exactly at the same time.

**Neils Bohr**

According to Bohr’s atomic model, in an atom the electron moves around the nucleus in a definite circular path known as orbits. This circular orbits are also known as the energy levels. He discovered that electrons travels in separate orbits around the nucleus. It is number of electrons in the outer orbit determines the property of the element. The electron keeps moving, when the electron jumps from one orbit to another with lower energy a light quantum is emitted.

** **

**Max Planck**

He was the originator of quantum theory of energy. In the development of quantum theory he made the assumption that energy was made of individual units known as * quanta*. His work significantly contributed to the understanding of processes at atomic and sub-atomic levels. Planck constant relates to energy in one quantum of electromagnetic radiation to that frequency of that radiation.

**String Theory**

This theory attempts to model the four fundamental forces of *gravitation, electromagnetism, weak nuclear force* and strong nuclear force under one grand unified field. In physics, string theory is a framework where the point like particles are replaced by one dimensional objects known as ** strings**. It states how strings propagates through space and interact with each other. This is also a theory of quantum gravity.

In today’s **Digital World** that we are living is fundamentally changing the contours of our life and is deeply dependent on the power of Quantum Mechanics. The computers running behind the scene are governed by the quantum power. Millions of ** transistors **are stacked together to make the

**. Transistors use materials developed to be used to control behavior at the quantum level. These chips are a product of the principle and process of quantum physics. Smart phones are driven by quantum technology.**

*computer chips*The Medical Resonance Imaging **(MRI)** in used in medical science, there is the role of quantum physics that work in the backdrop. The Global Positioning System **(GPS)** in our smart phones that quickly guides to the place we want to reach is powered by the computers. The computation is done at the GPS receiver using the satellite signals and the atomic clocks doing the support rely on the quantum mechanics. The energy efficient light produced by Light Emitting Display **(LED)** are powered by the quantum physics.

### Almost everything we do is enabled by the latent power of **Quantum Mechanics**, is at the microscopic level and we don’t see scenes behind the movie.

It is a different world.

We are deeply exploring this lesser known world.

The experiment is happening on a massive scale at the **Large Hadron Collidor**. There is light at the end of the tunnel. The matter is coming to terms. We are at the cusp of some massive change. The bigger thing that is going to come our way is from the innovation happening at this smallest level of atom.

It is all about now critically understanding the true nature and predictable behaviors of matter at the atomic and sub-atomic levels.

Nihar R Pradhan

Quantum theory and Einstein changed the way we used to think. Theory of Relativity proposed by Einstein continues to propel the direction of science and research till date. Thanks for writing such meaningful write-ups, Nihar

Indeed, scientists are constantly on the haunt for conquering new frontiers in science. With every invention something more gets revealed about what is still not explored. The way matter behaves remains at the heart of the matter. And its at the microscopic level. Life science is so much dependent on the development of physical science. Both are working together in solving problems that can make our life better in many ways. In the beginning of 20th century it was Theory of Relativity and in the 21st century Quantum Mechanics does possess the massive potential to transform the way we live our life.

Always great to have your thoughts…