Welcome to quantum tech!
When I was at the university, I was fascinated by the quantum computing course. It was a course that introduced me to this world. Unfortunately, it was not very accessible and did not explain the basics.
This blog is intended to be a simple approach to quantum computing and will explain the basics of it. I will also use IBM’s Quantum Experience program as well as many other sources in order to explain what happens around it.
In a world where quantum-safe encryption is not yet in widespread use, the threat posed by quantum computing to current cybersecurity measures is very real.
Quantum computing has the potential to become a game changer – if it can be made to work. The promise of quantum computers is that they will be able to solve certain types of problems much more quickly than conventional computers.
But there are many challenges. For example, qubits can store information in any of several states at once, which means they are perfect for parallel processing. But qubits are also notoriously fragile and tend to lose their state of superposition very easily.
Quantum computing has, for the most part, been a theoretical pursuit for several decades. In recent years however, with the advent of quantum annealing devices from D-Wave Systems and IBM’s efforts to create a universal quantum computer (although limited in scope), there is now a real possibility that the first applications of large-scale quantum computers will occur within the next few years.
The challenges associated with building a large-scale quantum computer are daunting and diverse. We need to prepare and position ourselves to take advantage of the first generations of large-scale quantum computers as they become available.
What is Quantum Computing?
Quantum computing is a relatively new paradigm for computation which utilises some of the concepts in quantum mechanics to perform calculations. This can be used to solve certain problems faster than would be possible using classical computers which have been around since the 1940s.
In quantum computing, we typically describe the state of a qubit using a vector in a two-dimensional complex Hilbert space ℂ2. Therefore, we can describe the state of n qubits using a vector in ℂ2n. The dimension of this space grows exponentially with the number of qubits.
The ability to efficiently simulate quantum systems is fundamental to problems like quantum chemistry and materials science, and to our understanding of how quantum computers might solve hard computational problems. To do so requires an efficient way to represent and manipulate these exponentially large complex vectors.
Quantum circuits are built up from gates that transform the state of a few qubits at a time. Similarly, if we can efficiently represent and manipulate these exponentially large vectors, then we can manipulate individual components in constant time, which will allow us to efficiently simulate transformations on many qubits at once.
A quantum computer is a system (hardware and software) that exploits the laws of quantum physics. Such a device would work based on the principles of quantum mechanics, which describe the behavior of particles on atomic and smaller scales. As such, quantum computers are fundamentally different from the binary digital electronic computers we use today.
In quantum computing, information is stored in qubits which can assume values of 0 or 1 or both simultaneously. This superposition principle allows a quantum computer to process much more data than a digital one by performing multiple computations at the same time.
A qubit (quantum bit) is a unit of quantum information – a two-state (or two-level) quantum mechanical system, such as the polarization of a single photon: here the two states are vertical polarization and horizontal polarization. In a classical system, a bit would have to be in one state or the other. However, quantum mechanics allows the qubit to be in a superposition of both states at the same time, a property that is fundamental to quantum computing.
Quantum computing is the branch of computing which uses quantum mechanics to process information.
Quantum computing was first theorized in the early 1980’s by Nobel laureate physicist Richard Feynman. Since then, quantum computers have been developed and used in various experiments and applications.
The field of quantum computing is still in its infancy, but it has experienced rapid growth in recent years, especially with the development of Google’s Sycamore processor and IBM’s Q System One. Quantum computers are just beginning to be used commercially, and corporations like Amazon have begun selling cloud access to quantum computers.
Quantum computing has the potential to greatly expand our ability to solve problems which would take conventional computers too long to solve, such as breaking encryption codes or simulating chemical reactions.
A quantum computer could run algorithms which a classical computer could not complete within its lifetime or ever!
We need to store and process information. Our modern society has become increasingly dependent on the speed, volume, and accuracy of our computing systems. However, current computers are limited to two states: 0 and 1, true or false. Unfortunately, this binary system is not enough to represent quantum objects like atoms and photons. These quantum objects can exist in a superposition of states; they can be both 0 and 1 at the same time!
Quantum computers exploit these properties. They can store more information in one place and process it much faster than classical computers. Everything we do on a computer is built upon simple calculations that take place 1s and 0s. Quantum computers would revolutionize how information is stored and processed by allowing many calculations to occur at once.