Quantum physics or quantum mechanics, the theory governing the microscopic world of atoms and particles, has become a buzzword in today’s day and age. This is no surprise, as it is counterintuitive and bizarre compared to other areas of physics, which makes it so dazzling and intriguing. But with this greater complexity comes a higher chance of confusion, which is prevalent in debates regarding quantum physics online or in its representation in various media and leads to many persistent myths and misconceptions. Below, we debunk the most common of these fallacies and shed light on the truth.
1. Schrödinger’s cat
Erwin Schrödinger’s thought experiment on whether a cat can be both dead and alive at the same time has become somewhat of a meme status in the modern online space. It suggests that a cat inside a box with a kill switch that activates via a random quantum event like radioactive decay could be simultaneously dead and alive, provided you do not open the box to make sure.
Quantum particles being in two states at the same time is one of the fundamental concepts of quantum physics and is called superposition. Scientists have successfully proven this via the renowned double-slit experiment wherein a singular quantum particle, such as a photon or electron, can pass through two different slits or openings in a wall at the same time.
This is possible because each state of a particle is also a wave. However, when sending a stream of photons through the slits one by one, this causes a pattern of two waves to arise and interfere with one another on a screen behind the slit. And since each photon had no other photons to interfere with upon going through the opening, it must have entered both slits simultaneously, interfering with itself.
But in order for this to work, the waves or states in the superposition of the particle entering the slits must have a well-defined relationship with each other, which is termed “coherent” in quantum physics. Experiments on superposition can be done with objects of increasing complexity and size.
That said, what does all this mean for the poor cat stuck in the box? Is it truly alive and dead at the same time as long as the box remains unopened? Naturally, a cat is different from an individual photon in a controlled environment, which is greater in size and complexity. Any coherence that the numerous atoms of our furry friend might have with one other will be far too short-lived.
This by no means points to the impossibility of quantum coherence occurring in biological systems but more so that it generally will not apply to larger creatures like cats.
2. Nature is non-local and unreal
According to Bell’s theorem, nature is “non-local”, or an object is not directly influenced by the immediate environment. One other common interpretation of this theorem is that the properties of quantum objects are unreal, i.e. they do not exist until measured.
However, the theorem only lets us say that quantum physics means nature is non-local and unreal if we assume a few additional things simultaneously. These include the ideas that there is only a single outcome for a measurement, cause-and-effect flow forward in time, and that our reality is not a clockwork universe wherein everything has been predetermined since the beginning of time.
Yet despite what the theorem is often said to claim, nature may very well be local and real if you stray from some of the things largely considered common sense, like time moving incessantly forward. Hopefully, further research can help narrow down the numerous potential interpretations of quantum physics. Yet, many of the options on the table, like the absence of free will or time flowing backwards, are just as absurd as abandoning the concept of local reality.
3. Nobody gets quantum physics
Nearly everyone has heard of Richard Feynman’s classic quote (which also paraphrases Niels Bohrn in this form) that goes, “If you think you understand quantum mechanics, you don’t understand it.” Now, the public believes quantum physics is nearly impossible to understand, even among physicists.
But the truth is that quantum physics is neither conceptually nor mathematically difficult for scientists when viewed from a 21st-century perspective. In fact, we understand the field quite well to the point that things like predicting quantum phenomena with extreme precision to building quantum computers are now all a reality.
Where the true difficulty lies is in figuring out a way to reconcile our intuitive reality with quantum physics. Yet, not having all the answers has never stopped humanity from making further progress in the realm of quantum physics.
There is no doubt that many mysteries are yet to be unravelled in the field of quantum physics, but it is best to first fully comprehend what it has already proven and cut through the misconceptions surrounding it. Keen on learning more about all the interesting concepts of quantum physics? Tuition Physics offers JC H2 and IP physics tuition in Singapore, taught by passionate physics tutors dedicated to helping you achieve your academic goals. To learn more about our programmes and syllabus, don’t hesitate to contact us today!