# Quantum Computing for Dummies

Computer savvy since 1984, Choreologist Juliette Kando shares her findings on the latest developments in quantum computing.

The increasing demand for computing power (by corporations, governments, and education) has grown to the point that even the most powerful supercomputers became inadequate. Using subatomic logic (a methodology that looks inside of atoms), quantum computers are much faster, cheaper to use, and exponentially more powerful than classical or even supercomputers.

Illustrated with several short experts' videos, this article hopes to give the layperson a glimpse into the marvels of quantum computing in the following segments.

1. How Do Computers Work?
2. Origin of Quantum Computers
3. Quantum Physics and Mechanics
4. Quantum Gates
5. What Is a Qubit?
6. Superposition and Entanglement
7. Quantum Peculiarities
8. Who Uses Quantum Computers?
9. Who Are the Top Players in Quantum Technology?
10. Philosophy and Ethical Considerations

Before getting into the magic of quantum computers, let’s recap on how classical computers work. If you are familiar with how classical computers work, scroll down to Step 2 for "Origin of Quantum Computers”.

## 1. How Do Computers Work?

Electric wires and circuits carry all the information in a computer. How do you store or represent information using electricity? Well, if you had a single wire with electricity flowing through it, the signal can be either on or off. A single wire can represent a yes or a no, true or false. To this end, computers only use 2 digits, 1 or 0. This on/off state of a single wire is a binary digit called a bit and is the smallest piece of information that a computer can store. If you use more wires, you get more bits to represent more complex information using the binary number system (1s & 0s).

### Binary Number System

As everyone knows, the decimal numbering system uses ten digits, 0 to 9, and each position represents a different value: 1,10,100,1000, etc, i.e. decimal numbering multiplies each position by 10. Not so in the binary system. The binary system only uses two digits: 0 and 1. Almost nobody today actually deals directly with ones and zeros, but they do play a big role in how computers work on the inside. Text (ASCII), Images (pixels), sound (waves), and videos can all be created, stored, and viewed with ones and zeros in the binary number system.

Now that we’ve cleared the air about classical computers, what is the difference between your laptop or phone and a quantum computer? How did it all start?

## 2. Origin of Quantum Computing

In the 1980s, Nobel Prize-winning American theoretical physicist Richard Feynman began pioneering the field of quantum computing by introducing the concept of nanotechnology. Nanotechnology or nanotech uses matter on an atomic, molecular, and supramolecular scale. To get to know the man, watch the next very interesting video in which Richard Feyman explains what the word "why" means to a computer (or to a human toddler for that matter).

## 3. Quantum Physics and Mechanics

Quantum Physics is the study of nature, matter, and energy at the most fundamental level, at a scale smaller than atoms, looking at particles like photons (light), phonons (sound), and particles inside an atom such as protons, neutrons, and electrons. Quantum Mechanics deals with the mathematical description of the motion and interaction of subatomic particles. At the heart of quantum physics is a concept called Amplitudes, which is a change to the rules of probability.

Amplitudes are explained clearly in the next video by professor Scott Aaronson, an American theoretical computer scientist at the University of Austin, Texas. If you’re in a hurry start at 3:03.

Scroll to Continue

### Quantum Mechanics and the Uncertainty Principle

Unlike in physics, where everything is defined precisely by numbers, a quantum mathematical equation is abstract, which means you cannot measure the exact physical properties of a particle’s position and momentum for sure. Because of the uncertainty principle, it has to be one or the other.

The uncertainty principle states that accurate knowledge of complementarity pairs is impossible. For example, you can measure the location of an electron, but not its momentum (energy) at the same time. Instead, a mathematical function called the wave function provides information about the probability with which a particle has a given property. The wave function can tell you what the probability is that a particle can be found in a certain location, but it cannot tell you where it is for sure.

Because of this uncertainty and other factors, you cannot use classical mechanics (the physics that describes how objects move) to predict the motion of quantum particles. That is why, on the hardware side, the logic circuit gates in a classical computer look very different from those in a quantum computer.

## 4. Quantum Gates

On the hardware side, classic computers’ material building blocks are logic gates as seen in the first image on the above picture. Those gates define options ‘AND’, ‘OR’, and ‘NOT’ and would have to be in one state or the other, no confusion there.

Quantum computers, on the other hand, use quantum logic gates, a circuit that allows the qubit to be in a coherent superposition (see below) of two states simultaneously! Superposition is a property that is fundamental to quantum mechanics and quantum computing.

But first, what is a qubit?

## 5. What Is a Qubit?

Just like the bit in a classical computer, a qubit is a quantum bit that is the basic unit of information in a quantum computer. It has something – a particle or an electron, for example – that adopts two possible states, and while it is in superposition, the quantum computer’s algorithms can harness the power of both these states simultaneously.

How can that be? This is because a qubit can only be certain of its answer to one question at a time. This is due to a fundamental uncertainty that exists within quantum systems with its superposition and entanglement properties.

## 6. Superposition and Entanglement

### Superposition

Imagine two mosquitos landing on the surface of a pond at two different points at the same time. Circular waves spread outward from each point, eventually overlapping to form an entangled figure of 8. This is a superposition of waves.

Similarly, in quantum science, objects such as electrons and photons have wavelike properties that can combine and become what is called superposed. Superposition is the ability of a quantum particle to be in multiple states at the same time.

### Entanglement

Imagine again, when you spin an upright coin on a flat surface, it’s in a state of superposition between its two faces -heads and tails. When a pair of electrons are generated, interact, or share proximity, their spin states can get entangled, which is what scientists call the quantum entanglement of electrons.

Entanglement is one of the most bizarre phenomena in the quantum realm. When two or more particles link up in a certain way, no matter how far apart they are in space, their states remain linked. That means they share a common, unified quantum state. So it appears that two quantum objects can form a single entity, even when they are well separated from each other.

For example, two members of a pair of qubits exist in a single quantum state. Changing the state of one of the qubits will instantaneously change the state of the other even when the particles are separated by a large distance. Quantum entanglement has been demonstrated experimentally with photons, neutrinos, electrons, molecules as large as buckyballs, and even small diamonds.

Because the concepts of entanglement and superposition are somewhat difficult to believe, watch theoretical computer scientist Scott Aaronson explain it all in the next video.

## 7. Quantum Peculiarities

### The Tunneling Effect

If you have a tennis ball and throw it at the wall. It bounces back and you can catch it. Now if that tennis ball is very very small, it will take on a waveform and tunnel itself right through the wall!

### Storing

Storing a quantum state – i.e. particles in superposition – is very difficult. Any interaction with the universe will disrupt it and cause errors. This is why quantum computers are shielded electro­magnetically and cooled down to almost absolute zero (−273.15 °C or −459.67 °F).

### Particles Can

• be in more than one place at the same time with superposition (as in a spinning coin).
• unify, (become one with another) at distances away with entanglement.
• play peekaboo, or grandmother’s footsteps with the double split effect.

### Double Split Effect

The unbelievable double split effect beats them all. It proves that if you watch photons (light particles) pass through two slits, they behave like particles and will go through either one or the other whole. But if you don't watch, the particles behave like waves and can go through both holes simultaneously! As shown in the next video, the Double Split Effect is one of quantum mechanics’ inexplicable phenomena.

## 9. Who Uses Quantum Computers and for What?

Quantum computing is still in its infancy but rocketing forward. Some current applications by large companies and governments are:

• Communication
• Computation and logistic
• Investment
• Pharmacy
• Coding cryptography
• Molecular modeling
• Mega statistic
• Traffic optimization
• Weather forecasting and climate change

## 10. How Big Is a Quantum Computer and How Much Does It Cost?

At the top, IBM has made a 127-qubit quantum computer. This is over double the size of comparable machines made by Google and the University of Science and Technology of China.

Google’s Sycamore quantum processor has 53 qubits. In 200 seconds, the machine performed a mathematically designed calculation so complex that it would take the world's most powerful supercomputer, IBM's Summit, 10,000 years to do it. This makes Google's quantum computer about 158 million times faster than the world's fastest supercomputer.

Commercial quantum computers cost around \$10 million and process more than 50 qubits. A 24-qubit quantum computer fits in a pair of boxes about as large as two large fridges.

At a lower range, SpinQ developed a smaller quantum computer for education and research. This machine can be linked to laptops and costs less than \$50,000. The new portable device is much less powerful, able to process just 2 qubits. Its volume is 70×40×80 cm and it weighs a hefty 55kg (121 lbs)—about the weight of a small adult.

## 10. Philosophy and Ethical Considerations

Thanks to centuries of innovative technology, human vision can now observe things that are, at the small end of the spectrum, as small as quarks (quantum particles) measured in *nanometers (nm = one-millionth of a millimeter).

### * How Small Is a Nanometer?

• A sheet of paper is about 100,000 nanometers thick.
• A strand of human DNA is 2.5 nanometers in diameter.
• A human hair is about 80,000- 100,000 nanometers wide.

At the far end, looking up and outward into space, we can see things several billions of light-years away. Amazing!

### Philosophy

The foundations of quantum mechanics and quantum metaphysics, collectively are called quantum philosophy, a subfield of philosophy of physics. After all this research, I have been developing my own philosophy on the quantum world where particles can …

• move in 4D (XYZT‒ T stands for time) and be in more than one place at the same time with superposition, then turn into waves that can pass through solid walls.
• use their entanglement powers to merge with another particle, even when that other particle is some distance away,
• plus, the mystery of being reactive to observation as in the Double Split Experiment. Imagine, particles don’t need security cameras, they somehow can “sense” that they are being watched.

Hang on a minute, but aren’t we all made of particles? If my particles can tunnel through a wall, why can’t I? Ah well, the probability of that happening is very, very small. That is because I would need every single particle in my body to become simultaneously superposed and turn into waves (when no one is looking). Apparently, waves that small can "tunnel" their way through solid matter.

## To Conclude

All I know is that quantum computers are part of the never-ending evolution of our exponential curiosity. While this article is only a nanometer nearest to understanding the quantum world, as always, we ask: “For the good of whom?” I leave you to debate the pros, cons, and ethics of quantum power with your friends.

If you think you understand quantum mechanics, you don’t understand quantum mechanics.

— Richard Feyman, theoretical physicist, Nobel laureate

## References

What Is Choreology?

IBM creates largest ever superconducting quantum computer

Quantum Computing for Everyone

A Study of Normalisation Through Subatomic Logic

What’s Inside an Atom?

Size of the Nanoscale

What is a Qubit?

Molecular Magnets to Act as Long-Lived Qubits

What Kind of Logic Gates Are Used by Quantum Computers?

What Is Superposition and Why Is It Important?

What Is Quantum Entanglement?

Entanglement Theory