The sci-fi brainiacs in Hollywood are good, really good. They draw us into their alternate reality universe over again with mind bending computer generated images. But there’s more to quantum mechanics than what you see on the big screen.
The recent Everything Everywhere All at Once is a prime example of this multiverse fixation. However, ‘quantum’ can also be a catch-all term for something us mere mortals can’t possibly understand. Like Futurama’s Professor Farnsworth and his calculated accusations that his punt on the ponies was fixed through quantum measurement of the race outcome. Right on professor!
Video: © Twentieth Century Fox, Curiosity Company, Rough Draft, Matt Groening
In an attempt to make the complex accessible, our quantum physicists have come up with 10 things about quantum that you should know.
Let’s break it down, shall we?
Quantum mechanics is a branch of physics that deals with the behaviour of matter and energy at the smallest scale. It describes the properties of particles such as electrons, photons and atoms that make up our physical world. Quantum mechanics may seem like an abstract concept reserved for scientists and physicists. But it actually has a profound impact on our everyday lives.
One of the most well-known applications of quantum mechanics is in electronics. The invention of the transistor, which forms the basis of all modern electronics, relied on the principles of quantum mechanics. Additionally, quantum mechanics is the foundation of quantum computing. It’s a technology that promises to revolutionise computing power and solve some of the world’s most complex problems.
Quantum mechanics also plays a significant role in medicine and biology. Magnetic resonance imaging (MRI) machines use the principles of quantum mechanics to create detailed images of the body’s internal structures. They have become an essential tool for medical diagnosis. Understanding the behaviour of subatomic particles has helped scientists better understand the fundamental processes that govern the human body, such as the way proteins fold and interact.
Now (drum roll) to our list
- The Cambridge Dictionary defines quantum as “the smallest amount or unit of something, especially energy”.
- Quantum objects are so small that classical mechanics can’t precisely describe their behaviour. Objects include atoms, ions of atoms, subatomic particles like electrons and photons.
- Quantum physics is the scientific study of these quantum objects.
- Quantum mechanics is the set of rules that describes the behaviour of these quantum objects.
- Quantum behaviour is non-intuitive and different to what we see at the everyday macro scale. But in truth, quantum mechanics have described quantum behaviour very well.
- Understanding how quantum objects behave is opening a whole new realm of technological possibilities.
- Quantum computers use our understanding of the above quantum behaviours. These enable us to ask a question and get a complex answer. With a classical computer (today’s ‘normal’ computers that use binary ones and zeros), we get a black and white ‘yes’ or ‘no’ answer. Using quantum, we get a probability based ‘maybe’ as an answer by virtue of the quantum superposition. This might not sound useful, but with the right approach to asking the question, the quantum computer can discount wrong answers and instead amplifying right answers.
- Quantum computers will excel at some computational problems, but for others the classical computer will remain optimal. For example, difficult mathematical problems like factoring large numbers into their prime factors. Many digital encryption algorithms used today rely on the premise that prime factorisation is almost impossible with classical computers. Prime factorisation is the process of working out which combination of prime numbers can be multiplied together to give a target number. Therefore, one major concern about quantum computers is that they could crack common encryption schemes relatively easily. Classical computers aren‘t well suited for optimisation of highly complex systems. For example, in transport networks the time to compute a good solution takes much longer than the changes in the system. It is anticipated that quantum computers will deliver exponential improvements in computational speed, allowing for real-time optimization.
- Quantum states can be very fragile and easily influenced by external factors such as magnetic and electric fields. People can exploit this by creating devices that control and use these interactions to create ultra-sensitive detectors. A well-known example is the magnetic sensor medical practitioners use to measure tiny electrical signals in the brain.
- Quantum communication uses the quantum state of the quantum object to hold and carry information. It’s secure because if someone intercepts the message it will collapse the quantum state. This will be apparent to the sender and receiver.
Some key definitions
Superposition is when a quantum object with two states (for example up and down or on and off) can actually be both at the same time. When the quantum object is observed, it instantly takes on one or the other state only. Probabilities help us understand this behaviour.
Entanglement is when two or more quantum objects are interdependent. One object cannot be described without reference to another and actions on one affect or make known properties of another.
Tunnelling is when a quantum object can pass through an energy barrier that most of the time it doesn’t have enough energy to clear. However, because of the probabilistic nature of quantum mechanics it sometimes does pass through the barrier.
So what’s next?
While we’re still in the early stages of quantum technology capabilities, the realms of possibilities are becoming apparent. Quantum applications will enable scientists and researchers to:
- Accelerate drug and materials development in healthcare
- Enhance national security and support defence
- Increase productive mineral exploration and water resource management for mining and other sectors
- Improve secure communications for industries like Space