Quantum Computing

Quantum computers are extremely powerful machines used to solve highly complex problems.

This story was created for the Google Expeditions project by Vida Systems, now available on Google Arts & Culture

Quantum Computing by Vida Systems

They operate very differently from normal computers, utilizing quantum mechanics rather than relying on binary language, and require specialized temperature conditions in order to operate.

The Quantum Computer

Quantum computers do exist and are being tested by large companies and organizations such as Google and NASA in order to offer solutions to difficult problems much faster than regular computers. Like the earliest binary computers, current quantum computers are physically large. 

Size

A quantum computing unit needs to be housed in a very large space. The room should be 10 feet high with 700 cubic feet of surface area. 

Tom Shain holds a computer chip with about 35,000 signatures of visitors to the Mars Exploration Rovers at the Jet Propulsion Laboratory.NASA

Chip

The actual quantum chip, the device that holds all of the bits that do all of the work, measures only about 1 square centimeter, the size of a thumbnail.

Refrigeration

Most of the quantum computer unit is designed to contain necessary refrigeration equipment. In order for the chip to work it has to be very, very cold.

Low magnetic environment

The quantum processor is an extremely delicate chip. Magnetic fields as well as radio frequency waves can easily disrupt its ability to perform reliable calculations and computing operations. 

Quantum particles

Quantum computing relies on objects called qubits (for quantum bits) to perform calculations. These particles are very, very small. There are currently 4 types of qubits used to develop quantum computers. All 4 of these particles rely on superposition to complete tasks.

Person

We’ll start by imagining just how small these quantum particles are. First, we begin with a human body, and then zoom in.

Arteries

Highways of arteries and other blood vessels along with nerves run through our bodies. We will need to zoom in even further than that.

Cell

We are now down to microscopic level and are looking at a cell wall. We need to keep zooming in quite a bit to reach qubit level.

DNA

Within an individual cell we can find DNA, the blueprint that forms who we are. However, we still need to get much closer.

Atom

Our DNA is made up of 5 types of atoms: oxygen, nitrogen, hydrogen, carbon, and phosphorous. Here is a single carbon atom.

Subatomic

Inside the atom we will see the electron field zipping around the nucleus of the atom. We are almost there now.

Qubit

One type of qubit uses a single electron to perform operations, one of the cometlike images here. The electron is stripped away and turned into an ion.

Other qubits

Other qubits are equally small; some researchers are developing computers using a single photon (a particle of light), others are using electric currents. An Australian team is using a single phosphorus atom.

Superposition and entanglement

Quantum computing relies on 2 unique phenomena that occur in quantum physics: superposition and entanglement. The mechanics behind both of these are, quite frankly, completely unknown. 

Superposition refers to the possible state of a qubit, entanglement refers to the relationship between 2 qubits.

Electrons

Superposition is a challenging concept to explain in a few sentences. Basically instead of being in 1 of 2 states, either “off” (blue) or “on” (red), an electron is in both of these states at the same time (purple).

Spin

Superposition states that electrons are traveling in all possible directions at the same time. Quantum computers give an idea of the likelihood of an electron being in a “spin down” or a “spin up” state.

Spin down

When an electron is in a spin down state the north/south poles are aligned with the natural magnetic field.

Spin up

When an electron is in a spin up state the north/south poles are reversed; its south pole is aligned to the north. Remember, electrons are in both states, and all states in between at the same time.

Entanglement

Quantum entanglement is another very difficult concept to describe in basic terms. Essentially, for an unknown reason, 2 electrons that were created together are forever entangled.

Behavior

So if one entangled electron changes, the other changes the same way at the exact same time. This occurs no matter how far away the 2 electrons are. Even with galaxies in between them, they will still both change instantaneously. 

Silicon bit vs. qubits

Quantum computers work in a radically different manner compared to binary computers. Binary computers use silicon bits. Each bit has 1 of 2 states; “off” represented as 0 and “on” represented as 1.

Quantum computers use an interesting quantum mechanic phenomenon called superposition in which a qubit can be both 1, 0, and all the states in between at the same time. 

Binary computers

As an example, let’s take 4 bits from an ordinary computer. As these are binary bits, each bit can either be a 1 or a 0.

Combinations

The total number of combinations possible with 4 binary bits is 24, so 16 different combinations could occur. The computer can use just 1 of these combinations.

Results

In order to find the needed result, a binary computer then needs to test each combination 1 by 1. This work is done in a series, or sequence.

Quantum

Thanks to superposition, the same 4 qubits can arrange themselves into the 16 possible combinations at the same time. This produces the results faster than a conventional computer.

Results

By using superposition and entanglement to our advantage, quantum computers are able to be much more efficient when testing combinations. This becomes extremely important when searching through large databases.

Conditions needed for quantum computers

Quantum computers are extremely sensitive. Extremely is actually an understatement, as even the tiniest of noise wavelengths can disturb the superposition of the electrons and render any outcomes useless.

Quantum computers are built very carefully to mitigate any potential outside influences. 

Temperature

Quantum computers need to be kept incredibly cold. The temperature of deep space is negative 455º Fahrenheit (-235ºC). Quantum computers need to operate colder than that, and some of them can only run below -460ºF (-237ºC).

Why?

Frigid temperatures help control qubits as much as possible. At these temperatures atom movement slows down. Other interesting phenomena also occur, seemingly breaking all theories about the 4 states of matter, but that will have to wait for another Expedition!

How?

Quantum computers use supercooled elements such as liquid hydrogen to cool the chip. The entire structure is built to cool the tiny chip, located right at the bottom of the machine.

Structure

The outside of the computer is covered with many layers, up to 16. These layers protect the chip from magnetic waves, sound waves and even light waves.

Uses of quantum computing

Quantum computers are extremely difficult to build and very expensive to maintain and run. However, a few big organizations such as Google and NASA have purchased a quantum computer, valued at around US$15 million. Why are people so excited about quantum computers? What can they do that ordinary computers cannot?

Speed

Quantum computers are much faster than ordinary computers at certain tasks. A quantum computer purchased by Google runs approximately 100 million times faster than a laptop. However, speed is not the main reason why quantum computers are used.

Analyzing outcomes

The reason quantum computers excite many people is their capability to solve very complex problems that can have billions of potential outcomes. In addition, they do it much faster than current computers.

Weather forecasting

Weather forecasting needs to take in a multitude of different bits of information and analyze it to predict outcomes. Quantum computers can quickly analyze data to produce more accurate weather forecasting, particularly helping people in cyclone and tornado prone areas. 

Molecular simulation

Molecules are very complex objects which ordinary computers simply can’t accurately map. Quantum computers can detail molecules and this may help doctors and researchers create effective medications.

Encryption and decryption

Quantum computers can be used to create unbreakable encryption codes. This could help improve cybersecurity, protecting online activities for institutions such as banks, stores, and research facilities. 

Particle physics

Physicists will use quantum computers to understand….quantum mechanics. Detailed simulations can be created using quantum computers which will in turn change the way physicists understand the world.

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