What are qubits? The basis of quantum computing

Qubits are to quantum computing as bits are to standard computers. Unlike binary bits, qubits can be in a state of 1 and 0 at the same time when a data measurement is taken. These elementary quantum-mechanical properties will revolutionize computing technology, with quantum computers being able to perform a million times better than the PCs we use today.

What are qubits?

The future of computing has a name: — qubits. Behind these cryptic values are the smallest, most basic computing units in quantum computing, “Qubits”. This is different in every way from the well-known bits that we use in our computers today. Qubits are defined by the two-state quantum system, i.e., they can have two states at the same time. They are the base for quantum computing.

In order to understand how qubits work, we first need to look at the three essential principles of quantum mechanics:

  • Superposition is a quantum system which can have two states at the same time. This can be illustrated by using an example of the binary system: Instead of 1 or 0, quantum systems can have as many different states at the same time until a measurement results in 1 and 0.
  • Quantum entanglement is a phenomenon found in quantum mechanics which was described as “a spooky action at a distance” by Albert Einstein. This is because there are two or more smaller parts which are entangled with each other and instead of having defined individual states, they create a combined system. If any smaller part is changed, any other part of the system connected to it will be changed as well.
  • Quantum collapse is the moment in which systems, which had previously found themselves in an undefined superposition, “collapse” when being observed or measured. This puts them into a defined state such as 1 or 0.

All three principles can also be found in qubits and, therefore, quantum computing. They are also the reason why governments and companies such as IBM, Google and Microsoft have a lot of hope for quantum computing. Although quantum computers are in reality a long way away, qubits can open unlimited possibilities in performance and our understanding of computers.

Qubits and bits: What’s the difference?

A bit does have one thing in common with a qubit: They are both the smallest computing and memory unit of their computer systems. However, this is where the similarity ends since, unlike the binary units we find in our computers today, the qubit is a quantum-mechanical measurement unit. So, what does that mean?

First, we need to understand how bits work. Since the first “Matrix” film, complex topics such as artificial intelligence and computer simulations have been more in the public eye and more people now understand the binary ones and zeros. A bit based on binary code is the smallest data unit in digital technology. Bits can have a state of either 1 such as “true/on” or 0 meaning “false/off”.

However, qubits are not based on binary code, so they don’t need to “decide”. On the basis of the quantum-mechanical superposition concept, a qubit can have both the 1 and 0 states. On top of this, it could also have a wide-range of states in between such as “a third of 0” or “two-thirds of 1”. Only when it is measured does a qubit get a defined binary state due to quantum collapse.

How much more processing power do qubits have?

The quantum-mechanical properties of qubits massively increase the computing performance of quantum computers when compared to standard computers. Even with 2 lots of 500 bits, you couldn’t process the same amount of data that could easily be handled by 500 qubits. 31 qubits, in turn, already have a memory capacity of 32 GB. Every additional qubit doubles the units of storage.

Here’s another example: A computer using only bits would need several million years to calculate the primary numbers of a 2,050-bit number. Quantum computers would complete this task in just a few minutes since they can make calculations at the same time and not one after the other. This obvious advantage could be revolutionary when processing and analyzing complex amounts of data.

How are qubits created?

In order to make qubits useable in quantum computing they need to be created. While silicon chips are normally used to process standard bits, quantum computers require new technologies. This is where we find differing solutions. For example, ions in magnetic, electric fields are “captured” or photon quasiparticles as well as synthetic and actual atoms are used. With the trapped ion solutions, the qubits can be measured using microwave energy. Google used quantum chips, in which electricity flowing in a circle respectively represents a qubit. In this instance, the qubits are measured using microwave energy as well.

Using qubits in quantum computers doesn’t just offer more performance. New hardware, software and programming approaches are also necessary to process the qubits being read and stored in quantum logic gates. Since this causes a very fluid and volatile quantum system, computers must be able to reliably connect quantum bits in their millions.

Another important aspect of current quantum computer technology is proper cooling. When creating the powerful qubits, as with all computer systems, heat is created. For the best and safest performance, quantum computers need to be cooled down close to absolute zero (-273.15 degrees Celsius).

Possible usage areas with qubits

It’s going to be some years before quantum computers find their way into our daily lives. This requires new technologies and a change in how we think about how computers work. When we get there, qubits offer a wide range of advantages which can be used across the board. Among these are:

The future of qubits and the technical hurdles and opportunities

If you believe the multinational technology companies such as IBM, Google and Microsoft, it’s just a matter of time until we get the first practical quantum computer. Millions have been invested in the technology and companies such as Google AI or D-Wave are proof that quantum computing is the future. Among the most powerful quantum computers at the moment is IBM’s “Eagle” with 127 qubits.

On the other hand, on October 23, 2019, Google AI announced that its Sycamore chip had solved problems that even the most modern supercomputer could not. This milestone was aptly named “quantum supremacy”. Before the complete superiority of quantum computers is truly known, we will first need new technologies, software and programming languages.

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