How Quantum Computers Work and Why They’re So Powerful

Whenever you take a closer look at quantum computers and how they work, it’s almost surreal. Not many of us are aware of the massive leap these supercomputers represent in processing power.

As mysterious as quantum physics has become to the average person, the same can be said about quantum computers. Their future trajectory will easily surpass today’s most powerful computers.

The role of quantum computers

Bear in mind that quantum computers aren’t here to replace conventional computers. There is no way that could happen because traditional computers solve too many everyday problems. And they’re also too economical and too easy to use.

Instead, quantum computers will be reserved to address the cutting-edge projects in virtually every field – ranging from social issues to engineering methods to pharmaceuticals research. Many companies are already designing and experimenting with research projects that are ideally suited for the newest supercomputer.

A prevailing problem for our society, in general, has been our inability to process the mountains of data we generate. We need the processing power to analyze data in a timelier manner. There is where quantum computing methods will earn their keep.

The real secret behind the power of a quantum computer is how it generates and processes quantum bits, also known as qubits.

What is a qubit?

qubitWe are familiar with the term ‘bit’ because we define bits of information generated in today’s conventional computers. A bit is simply a stream of electrical pulses that represent either a 1 or 0. All things created by current computers are a long string of bits.

Rather than bits, a quantum computer uses qubits, which are comprised of subatomic particles like photons and electrons. As you might imagine, creating and processing qubits is both an engineering and scientific challenge.

Some companies choose to use superconductors that can be cooled to temperatures that are colder than deep space. Other companies approach the process by trapping individual atoms in electromagnetic fields that exist on silicon chips within ultra-high-vacuum chambers. Both approaches have the same goals of isolating qubits within a controlled quantum state.

Qubits possess some rather outrageous quantum properties that allow them to generate far more computing power than the same number of ordinary binary bits. One such property is called superposition, and another known as entanglement.

What is superposition?

Qubits are capable of representing countless potential combinations of 1 and 0 simultaneously. This unique ability to represent multiple states is superposition. To lift qubits into superposition, scientists manipulate them with microwave beams and precision lasers.

Because of this counterintuitive property, quantum computers with many qubits in superposition can blast through massive numbers of possible outcomes simultaneously. The result of a calculation is rendered only when the qubits have been measured. After this, they collapse out of their quantum state into either a 1 or 0.

What is entanglement?

qubitsEntanglement is where pairs of qubits exist in one quantum state. Thus, whenever the state of one qubit is changed, the same change is instantly applied to the other entangled qubit. Researchers have discovered that this will happen in a predictable way – even when extremely long distances separate them.

As to how and why entangled qubits work like this remains a mystery. However, it’s one of the critical reasons that quantum computers are so powerful. In conventional computers, when you double the number of bits, you double its overall processing power. But because of entanglement, the addition of qubits to a quantum computer creates an exponential increase in its ability to process data and information.

Imagining the plethora of quantum algorithms that could be designed and executed at this quantum level explains all the excitement about them.

But it’s not all good news. One problem with them is they are far more prone to errors than conventional processors. The reason for this is something called ‘decoherence.’

What is decoherence?

Decoherence is when the quantum behavior of qubits decays and disappears. Because their quantum state is so fragile, the slightest change in temperature or a tiny vibration – known as outside ‘noise’ – can cause them to fall out of superposition before it has finished its assigned task.

Because of their fragile nature, we’ve seen scientists attempt to protect qubits by putting them in vacuum chambers and supercooled environments. Despite these precautions, noise still manages to induce errors in calculations.

Quantum algorithms that are cleverly designed can compensate for some of these errors, and the addition of more qubits also seems to help. But as it stands, thousands of standard qubits are required to generate a single, reliable one – and these are called ‘logical’ qubits. Thus, just to get an adequate number of logical qubits, a quantum computer must devote lots of its computational capacity.

This brings us to the quantum brick wall that scientists are facing. Thus far, researchers have not been able to create more than 128 standard qubits. So we’re quite a few years away from developing that quantum computer that’ll be useful.

Fortunately, this quantum brick wall hasn’t slowed down the efforts of computer researchers who seek to find an answer.

What is quantum supremacy?

quantum computersQuantum supremacy is the ultimate goal of researchers. It represents that point where quantum computers can perform mathematical calculations that are way beyond the capabilities of the most powerful supercomputers. And to do so reliably.

Currently, no one yet knows how many qubits would be required to achieve such a goal. One reason is that the goalposts keep moving. Other researchers continue to find new ways and algorithms that boost the power of classical computers, and the hardware of supercomputers keeps improving as well.

Nonetheless, quantum computer researchers and their sponsors continue working diligently to reach quantum supremacy as they compete against the most powerful supercomputers on the planet.

And the research world at large hasn’t given up the cause either. Many companies continue experimenting with them now – instead of waiting for supremacy. Several firms have even allowed outside access to their quantum machines.

What will the first quantum computer be used for?

There are many promising applications of quantum computers. One such approach is the simulation of matter at the molecular level. Automakers are experimenting with quantum computers to simulate the chemical composition of things like electrical-vehicle batteries to enhance performance.

Major pharmaceutical firms use them to compare and analyze compounds that may find new drugs. They can accomplish what previously took humans years to accomplish using conventional methods in just a few days.

These quantum machines are phenomenal at analyzing numbers and solving optimization problems incredibly fast. This ability alone makes them extremely valuable in a broad spectrum of disciplines.

Final thoughts

Even though it could take several years for quantum computers to reach their full potential, it appears to be well worth the effort.

One thing that is working against them is that businesses and universities experience a growing shortage of researchers with the required skills. Efforts to bolster STEM candidates are falling woefully short of expectations.

Secondly, there are not enough suppliers of the required vital components to support quantum computers. And many companies have shifted their priorities elsewhere at present.

Hopefully, we will be able to overcome these obstacles and reach our quantum goals. These new computing machines could completely revolutionize entire industries and boost global innovation to levels never seen before.