Step By Step Guide to Quantum Computing

What Is Quantum Computing?

Utilizing concepts from basic physics, quantum computing is a novel method of computation that can swiftly tackle extraordinarily complicated problems.

Turn over a coin. Is it heads or tails? Yes, once we observe the outcome of the toss. However, neither heads nor tails show on the coin while it is still in the air. There's a chance of both.

The more straightforward basis of quantum computing lies in this gray area.

Learn from and interact with senior McKinsey quantum computing specialists directly.

In the Munich office of McKinsey, Ondrej Burkacky holds a senior partner position. Similarly, in the Vancouver office, Dieter Kiewell and Jared Moon are senior partners. In the London office, Alexandre Ménard holds a senior partner position. In the Bay Area office, Mark Patel holds a senior partner position. Lastly, Rodney Zemmel holds a senior partner position in the New York office...

The development of quantum computers promises to revolutionize computing. Computing has changed as a result of quantum computing. Beyond the capabilities of current computers, they can resolve extremely complicated statistical issues. Quantum computing is one of the upcoming major technological trends because of its immense potential and momentum. Of the three primary fields of future quantum technology,

The advancement of quantum computing holds the potential to completely transform computing. Quantum computing has completely transformed the field of computing. They can answer very complex statistical problems that are beyond the capacity of modern computers. Given its enormous potential and velocity

Why do we want quantum computers?

Quantum computers are expected to solve some issues more easily than traditional, classical computers, which are currently almost unsolvable. It is anticipated that quantum computers will also threaten existing cryptography techniques and open up new avenues for totally secret communication.

Our ability to study, simulate, and work with other quantum systems will be aided by quantum computers. This capability will advance our knowledge of physics and impact the design of objects engineered at scales where quantum mechanics is relevant, including materials, computer chips, communication devices, energy technologies, scientific instruments, sensors, and clocks.

The applications that arise for quantum computers may surprise us, just as few of the uses of classical computers and related technologies that we know today were conceivable in the 1950s.

How does a quantum computer work?

There are certain similarities between classical and quantum computers. For instance, logic gates, circuits, and chips are typically found in both kinds of computers. They use a binary code of ones and zeros to encode information and algorithms—basically sequential instructions—to direct their activities.

The ones and zeros are encoded by physical objects in both kinds of computers. These devices encode bits, or binary digits, in two states for use in classical computers. Examples of such states are off-current and up-and-down magnetism.

Quantum bits, or qubits, are used in quantum computing and have a different way of processing information. A qubit can simultaneously represent one and zero until its state is measured, in contrast to classical bits that can only represent one or zero.

Moreover, it is possible for the states of several qubits to be entangled, or quantum mechanically connected. Quantum computers possess capabilities not seen in classical computing due to superposition and entanglement.

Lithography is a printing technique that can be used to create qubits by nanoengineering so-called artificial atoms, such as circuits of superconducting qubits, or by manipulating atoms, electrons, or electrically charged atoms known as ions.

Do quantum computers exist?

For almost ten years, there have been evolving versions of quantum computers. Working quantum computers are already owned by several IT companies, who also provide resources for software development and programming languages that go along with them.

Rapid advancements are being made in the technology that has the greatest potential applications: quantum gates that manipulate qubits via logical operations. These days, most computers of this kind have less than 100 qubits. The qubits are housed in nested chambers that protect them from magnetic and electric interference and cool them to almost absolute zero temperature, keeping them in a quantum state.

In 2019, a quantum computer achieved a significant technological milestone by completing a particular computation in a fraction of the time required for a traditional supercomputer to solve the same problem. The achievement is regarded as a proof of concept, and it will likely take years before this kind of quantum computer is used to solve real-world issues.

Although it is restricted to a certain type of calculation, quantum annealing, an alternative method of quantum computing, is further along in development. Thousands of qubits are used in a quantum computer housed in a cryogenic refrigerator in this method to rapidly approximate the optimal solutions to complicated problems. The method is restricted to mathematical issues with numerous variables and potential solutions known as binary optimization problems. A few businesses and organizations have either bought these kinds of computers or rented time on new models to deal with scheduling, design, logistics, and materials discovery issues.

When will broadly useful quantum computers be available?

Years may pass before general-purpose quantum computers are used to solve a wide range of real-world issues. They will likely need thousands of qubits to perform meaningful work. There are difficulties with scaling up.

Big quantities of qubits are more difficult to isolate, as they collapse or decohere when they come into contact with nearby molecules or magnetic fields, losing the crucial yet brittle qualities of superposition and entanglement. The likelihood of errors in the machine increases with the number of qubits since the environment might perturb individual qubits.

To maintain accuracy even in the face of faults, theorists and experimentalists devise methods to lower errors, extend the amount of time qubits can remain in quantum states, and improve the fault tolerance of the system.

Scientists are improving current technologies and creating new designs for qubits and quantum computers. It will take time for both more established and less proven tactics to prove their worth, grow in reliability, and reach their full potential. 

Limitations of Quantum Computing

There is a lot of room for advancement and problem-solving in many areas using quantum computing. It does, however, currently have certain restrictions.

• Any perturbation in the qubit environment, no matter how little, can lead to decay or decoherence. Computations collapse as a result, or errors are made to them. As previously mentioned, during the computation phase of a quantum computer, it needs to be shielded from all outside influence.

• We still haven't mastered error correction during the computing phase. This raises the possibility of computation errors. Qubits cannot benefit from the traditional error-correcting techniques employed by classical computers since they are not digital bits of data.

• The data may become corrupted when retrieving computational outcomes. Promising developments include the creation of a specific database search algorithm that guarantees that the process of measurement will induce the quantum state to decohere into the solution.

• It is still early to properly perfect quantum cryptography and security.

• Quantum computers can't reach their full potential for useful applications due to a scarcity of qubits. As of 2019, researchers have not yet produced more than 128.

According to Iberdola, a global energy leader, "quantum computers must have almost no atmospheric pressure, an ambient temperature close to absolute zero (-273°C), and insulation from the earth's magnetic field to stop the atoms from traveling, hitting one another, or reacting with their surroundings."

Furthermore, because these systems only run for very brief periods, data becomes destroyed and cannot be saved, making data recovery much more challenging. 

The Bottom Line

The world of quantum computing is not like the world of classical computing. It makes use of qubits, which have simultaneous states of 1 and 0. Bits are used in classical computers, and they can only be 1 or 0.

Quantum computing is therefore far more potent and quick. It is anticipated that it will be applied to numerous highly difficult yet valuable activities.

Despite its current limits, it is ready to be utilized by numerous powerful businesses throughout numerous industries.