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Tag: quantum-physics

  • Building Our Future

    This is the final blog in this trilogy on the fascinating world of quantum physics, and yes, quantum mechanics has opened my eyes to a whole dimension of possibilities. In fact, quantum mechanics is a field of science that we use all the time. If I am being honest, it is probably something that we rely on a bit too much. So, what is the biggest use case of quantum physics in today’s day and age? Quantum is responsible for all the buzz around AI. All the top companies like Microsoft, IBM and DeepSeek are working on a branch of computing called quantum computing that can not only help progress AI but do things that even normal supercomputers would find impossible.

    Quantum computing is an emerging field of computer science that harnesses the unique qualities of quantum mechanics to solve problems beyond the ability of even the most powerful classical computers. It can solve problems that a normal computer could never solve, in a matter of months. They are being used for complex tasks that we could never imagine understanding, for example, to cure cancer through simulations or representing protein folding for doctors and biologists respectively (both of which I have been told are very complex areas of science). Both of these issues were considered impossible but necessary to tackle and now with the help of these super computers, the possibility dawns closer.

    Quantum computers have two main responsibilities: modelling the behaviour of physical systems as well as identifying patterns and structures in information; something humans and computers can do, but the efficiency of a quantum computer is unmatched.

    The four most important principles when thinking about quantum computing is superposition, entanglement, decoherence and interference. The most important of which is superposition, which derives from the basics of quantum mechanics, the theory of Schrodinger’s cat. The principle of superposition is when two or more waves overlap, the resulting disturbance is equal to the sum of individual disturbances, but each wave does this without affecting one another which means their characteristics stay independent. Simply speaking, imagine touching the surface of a lake at two different points at the same time. The waves would spread outward until they eventually overlap. This is a superposition of water waves, but this same concept can happen with any waves. In mathematical terms it is a similar concept to how a square root can have two possible solutions, e.g. the square root of 9 can be 3 or -3.

    When an electron is in superposition, its different states can be thought of as separate outcomes each with a different probability. However, the outcome is only known until it happens which is when the superposition collapses. It is science’s way to be able to exist in multiple different states at the same time.

    Sunlight itself is a superposition of light. White light which we see from the sun and most man-made light sources, is a superposition of all the colours. The formation of a rainbow occurs when the superposition collapses as the light is refracted through rain droplets. There have been many experiments to prove this idea, theoretical and physical. The most famous example being the Double Slit Experiment carried out by Thomas Young.

    Superposition is enormously important in quantum computing as this is how these machines store data. Rather than storing data in a bit, the smallest unit of data represented by a 0 or 1, they store data in qubits. These qubits are often created by manipulating and measuring quantum particles specifically photons and electrons as they are very small. A qubit is special as it can store data as a 0 and a 1 until it is measured. Therefore, the possibilities of storage can be 0, 1, 00, 01, 10, 11. As you can imagine, if one qubit holds so many combinations, and each combination represents a bit of data, then you can store vast amount of data with the same number of bits. When someone wishes to access this data, the multiple states collapse to form one single binary bit possibility, where it can be registered as a 0 or a 1.

    Quantum mechanics is a growing part of our world and frankly where all the new innovations and discoveries lie, as well as the fascinating new world of AI. Qubits could be the secret to an eco-friendlier way of storing data without thousands of litres of water wasted cooling the data centres. If like me, you are interested in science mixed with two of the most relevant subjects, climate change and AI, then this is where our future understanding lies. Quantum mechanics is a fundamental part of all modern studies, and I believe that quantum computing in particular is a field that requires more great minds.

    If you found this interesting and would like to read more on the subject I would recommend these websites;

    What Is Quantum Superposition? – Caltech Science Exchange

    Principle of superposition | Definition, Examples, & Facts | Britannica

    What Is Superposition? (Definition, Examples) | Built In

    What is a qubit? | IBM

    What Is Quantum Computing? | IBM

    What is Quantum Computing? – NASA

    Difference Between Bits and Quantum Bits – GeeksforGeeks

  • The Beginning of the Unthinkable

    The first blog in a three part series on the modern marvel of the century: quantum mechanics.

    But what exactly is quantum mechanics, and why has it fascinated scientists for over a century? From the strange behaviour of particles such as photons and quarks to the possibility of revolutionary technologies like quantum computers, quantum mechanics lies at the centre of some of the most exciting ideas in modern science. Understanding it means stepping into a world where the rules of everyday life no longer seem to apply. Albert Einstein himself had a love-hate relationship with the idea. It challenges you to forget everything you think you know and embrace the unthinkable.

    Quantum mechanics is probably the second most sought-after field in physics, following astrophysics. It is where ground breaking theories emerge, strange ideas challenge our understanding of reality, and physicists dream of having a discovery or theory named after them.  Recently, quantum computing has pushed quantum mechanics further into the spotlight, with new breakthroughs and mysteries appearing almost every year.

    Quantum mechanics is the description of the behaviour of subatomic particles such as photons and electrons, how they work and how they interact with light. Richard Feynman, a physicist in the mid-1900s said that particles are particles (not waves) and they can hop from place to place with a particular probability. To calculate the probability that the particle will be at a different place later is as follows: assign a probability to every point in the room and then add them up. This is called the path integral formulation and can be used to calculate the probability of a particle travelling from point A to B. If a particle travels from one corner of a room to another, the path integral formula can be used to calculate what the probability of that particle moving to another point in the room is.

    Before the turn of the 20th century, scientists believed light was a transverse wave and particles could never be waves. According to Newtonian physics a hot object should emit infinite energy at short wavelengths. Red light gives out some energy; blue light gives out more energy and tiny wavelengths like ultraviolet gives out huge amounts of energy. Their math stated that a hot object should pour out endless energy in tiny wavelengths. However, there are some clear problems with this theory as it would mean some objects would have infinite energy which means, that energy would come from nowhere. We now know that this would go against the theory of conservation of energy and evidently made no sense. Their mistake became known as the Ultraviolet Catastrophe.

    Max Plank in 1900 had a bold idea. He said that light energy does not come in smooth endless amount but instead it comes in tiny packets, called quanta. For example, you cannot use half a coin, you must use a whole coin. This idea meant that very tiny wavelengths need bigger energy packets (quantum), which meant that shorter wavelengths emitted more energy.

    Einstein expanded on this further. He thought, what if light itself was made up of quanta. The colour of the light tells you how ‘energetic’ it is. The shorter the wavelength, or the more purple the colour, the stronger the packets. So, in theory a blue hot iron would actually emit more energy than a red-hot iron. Einstein used this to explain the photoelectric effect. This is when shining dim blue light on metals could knock electrons out, but very bright red light sometimes could not. This led Einstein to believe that the energy was not about the total brightness, rather about how strong each tiny packet is. The blue light had a small number of large packets, and the red light had a large number of small packets. He called these energy packets, photons.

    Photons are a massless particle which means they do not feel a gravitational attraction. They move at the speed of light and have no rest mass; this means that a photon is always moving at the speed of light. These photons sometimes acted like waves and sometimes acted like particles. This meant that tiny particles could be in many possible states at once and its state only becomes definite once measured.

    This arises from Schrödinger’s theory that a cat can be both dead and alive at the same time. He imagined that a cat is placed in a box with radioactive material that has a 50% chance of killing the cat in the next hour. At the moment just before you open the box, the cat is both alive and dead at the same time. It is only once you open the box that the cat’s single state is visible. This quantum theory perturbed Schrödinger so much that he gave up physics and moved to biology.

    Quantum mechanics began as an attempt to explain strange mysteries about light and atoms which normal Newtonian physics simply could not explain, but it ended up completely changing our understanding of reality itself. From photons and wave-particle duality to uncertainty and superposition, quantum theory reveals answers to problems that had bizarre solutions earlier. Although many of its ideas seemed confusing at first, quantum mechanics has helped scientists build technologies like lasers, computers, and MRI machines, while also opening the door to future innovations such as quantum computing. Most importantly, it reminds us that not all questions are answered and certainly not all questions have arose.