What is known as a quantum computer has been the subject of films and series dozens of times throughout history. Although the original concept may sound like science fiction, the truth is that quantum computers are already a reality . As their name suggests, this type of equipment takes advantage of the properties of quantum mechanics to solve certain problems that classical computers are unable to solve, problems we will discuss below.
Quantum computers: what they are and how they differ from a traditional PC
Before discussing the differences between a quantum computer and a conventional computer, it’s helpful to understand the nature of the term “quantum,” which in this case refers to the type of information that these types of computers handle.
As is well known, conventional computers work with the simplest unit of information known to us, the bit. This unit contains exactly two states of information, subdivided into 0 and 1. In the case of quantum computers, the smallest unit of information is known as a qubit .
Unlike a bit, which can only hold a single combination, a qubit can hold a simultaneous combination of 0 and 1. This leads to more complex units such as bytes, which are simple groupings of bits. It’s worth noting that the natural state of a qubit is represented by subatomic particles , such as photons or electrons.
To process this type of information, quantum computers require the use of certain systems and materials that are resistant to these types of particles. In other words, the devices don’t have a conventional structure, but rather rely on a series of superconducting circuits whose cooling is designed to reach absolute zero , thus isolating the particles in a controllable state, just like any other process involving quantum physics.
Quantum mechanics and qubits: how quantum computers work with information
We’ve already discussed how qubits can contain different strings of 0s and 1s at the same time. This is because qubits can be represented in different states. To achieve this, quantum computers require the use of a series of systems to achieve what is known as quantum superposition, which is nothing more or less than the ability to represent multiple states at the same time —that is, multiple strings of 0s and 1s. This means that the information contained in these types of particles is much greater than what we can find in a byte.
Current systems are made up of microwaves and precision lasers that allow the state of qubits to be controlled. In fact, one of the great challenges of current engineering relates to these systems and their design. Creating a system capable of controlling these states while maintaining the qubits in their natural state will increase the possibility of working with vast amounts of information to levels never before seen . Another of the great challenges of current engineering is related to the combination of different qubits into groups known as chains, which overlap through what is known as quantum entanglement, a process that explains the connections between different units of quantum information.
This phenomenon is used to describe the pairwise grouping of qubits. In the same way that bits are entangled to form a byte, the grouping of this unit follows the laws of quantum mechanics. The problem is that the current laws of physics do not explain this phenomenon , and the control capacity is subject to errors and computational failures. And this is one of the major problems with quantum computers: the probability of errors when performing mathematical calculations.
This is due to the very behavior of qubits when interacting with each other and creating pairs with the other particles in their surroundings. As we indicated in previous paragraphs, controlling qubit states is one of the major challenges of current engineering , as current systems attempt to address what is known as quantum incoherence.
To achieve this, quantum computers must be isolated in a sterile environment free from sudden temperature changes , moisture, dust, or any other type of interaction with the environment inside the computer. This is why most computers are installed in vacuum chambers or industrial refrigerators. After all, any disturbance in the environment can lead to the loss of qubits or their clouding, meaning that the resulting calculations may contain errors.
Such is the difficulty of grouping qubits that the greatest achievement in current engineering has grouped only 128 qubits . This difference with respect to conventional computers is known as quantum supremacy, which is related precisely to the possibility of solving calculations that conventional computers are unable to solve, regardless of their computing power. In 2019, Google announced that it had achieved quantum supremacy with its own equipment . A year later, it was China that announced that it had reached this milestone through a research group from the University of Science and Technology of China in collaboration with Tsinghua University in Beijing.
The race to develop a quantum computer for use
To date, very few companies have participated in the development of this type of equipment due to the investment and difficulty of advancement. The best-known currently are Intel, Google, and IBM, which are in a race to develop the first viable quantum computer. For example, Google’s quantum computer, called Sycamore, has a capacity of 54 qubits and is capable of performing calculations that a conventional computer would take approximately 10,000 years to complete in just 3.5 minutes. That’s nothing.
As for Intel’s developments, the company launched its own chip in 2020, known as Horse Ridge. This chip allows for the integration of quantum processors with up to 128 qubits , the limit achieved to date. Meanwhile, companies such as D-Wave, which are involved in the development of this type of equipment, have proposed their own computers to the scientific community in the fight against COVID-19. IBM has also created its own commercial quantum computer, called the IBM Q System One.