The IBM quantum processor.
If the 19th century was the machine age and the 20th century the information age, the 21st century will be the quantum age. It is not hyperbole. William Daniel Phillips, Nobel laureate in Physics in 1997, believes that quantum computing represents a technological leap without comparison to those we have experienced so far, even greater than that between the abacus and current computing.
Quantum mechanics arises from early last century as the field of physics that describes the behavior of nature at subatomic levels (for example, of particles such as photons or electrons), for which classical mechanics could not find a satisfactory solution. Later, in the early eighties, the American physicist Richard Feynman proposed the construction of a computer whose internal states were quantum variables. This Nobel laureate, along with fellow American Paul Benioff and Russian mathematician Yuri Manin, laid the foundations for this new computation, thus starting the second quantum revolution. This attracted the interest of the security agencies of several governments, when the American physicist Charles Bennett and the Canadian Gilles Brassard proposed the first quantum cryptography protocol and the American mathematician Peter Shor an algorithm that drastically reduces the execution time of the factorization of numbers, one of the foundations of today's cryptography
Like classical computing, it is based on the concept of bit (which can take the value 0 or 1), in quantum computing the qubit (from the English qubit, quantum bit ), is the minimum unit of information. Unlike the bit, which can only be in one of these two states, the qubit can be simultaneously in states 0 and 1. It is as if we went from a light switch that turns it off or on, to one that leaves us have many intermediate states. Thus with 10 qubits we would have 1,024 simultaneous states and, each time we add a qubit , we double the computing power.
It must be taken into account that generating and handling qubits is a huge scientific and engineering challenge, since it is necessary to avoid that the qubits interact with the environment until they are measured, for which, in some cases, the circuits are cooled to temperatures lower than that of deep space (close to absolute zero, -273 degrees Celsius). Despite this, today quantum computers still have many errors, since the coherence of the values of the qubits is lost.
There are two ways to work with quantum computers. One is based on the so-called quantum annealing ―used by the D-Wave company― in which the problem to be solved is made to correspond with a model whose solution is the lowest energy state of the system and which are adequate to run optimization problems. The other is that of computers that support gate-based quantum computing ―used by IBM, Google or Rigetti―, in which a problem is decomposed into a sequence of primitive basic operations, which are performed using quantum gates. It must be taken into account that quantum computers do not replace current ones, but rather coexist in hybrid architectures in which a classical computer sends the appropriate instructions to the quantum computer, collecting and processing the results that it returns.
Quantum computers do not They only allow us to simulate nature much better, but also to execute algorithms that for “classic” computers are impractical, since they would take too long – in some cases, even the largest supercomputer in the world, several million years – or would require an almost infinite memory . In fact, in 2019 Google announced “quantum supremacy” with an experiment designed by the Spanish Sergio Boixo : a quantum computer managed to do in a few minutes something that would take a conventional supercomputer thousands of years. PPT There are hundreds of interesting applications for this new kind of informatics in fields such as economics and financial services, chemistry, medicine and health, logistics and supply chain, energy and agriculture. And, of course, quantum computing has a fundamental impact on cybersecurity and Artificial Intelligence. This has prompted many governments (the United States, the European Union, the Netherlands, France or Germany) to include quantum technologies in their research agendas and ecosystems.
In order to contribute to making quantum computing a reality, a group of researchers and computing professionals [including the signatory of this article] proposed in the Manifesto on Quantum Software Engineering and Programming , the everyone's involvement: companies and professionals, identifying projects that can benefit from this technology; the scientists, trying to solve the outstanding questions; governments supporting research and transfer, and academics, considering quantum computing in curricula and study plans. Quantum computing offers the opportunity to experience the same as the pioneers of computing in the sixties of the last century and be protagonists of this new era.
Mario Piattini Velthuis. Professor of Computer Languages and Systems at the University of Castilla-La Mancha
Chronicles of the Intangible is a space for dissemination of computer science, coordinated by the academic society SISTEDES (Society for Software Engineering and Software Development Technologies) . The intangible is the non-material part of computer systems (that is, software), and here its history and its evolution are related. The authors are professors from Spanish universities, coordinated by Ricardo Peña Marí (professor at the Complutense University of Madrid) and Macario Polo Usaola (professor at the University of Castilla-La Mancha).
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