Category: jIAPS

Author: Jan (Jack) Beda, University of Edinburgh, UK

Let’s begin with polarized sunglasses. You may have them. Why did you get such a fancy pair? Maybe you’ve been told they reduce glare? They do, in fact. All the light that bounces around in our universe has a polarization. A “direction” in which the electromagnetic fields wiggle. Light can wiggle up-down or left-right (and in a few other ways). It turns out that when light is reflected off of water and other substances, it becomes “partially horizontally polarized” (1). That is to say, more of the light wiggles left-right than up-down. Your fancy polarized sunglasses include a polarizer that only lets through the up-down light, and so all of the horizontally polarized light (the glare off the water) gets cut out.

Now, you can probably already figure out what happens if I take two polarizers and put them perpendicularly on top of each other. Let’s say the first one blocks the up-down light, then the second one blocks the left-right light, and so if you put them together, all of the light is blocked, and you see nothing. As you rotate the polarizers with respect to each other, you are able to change how much light gets through. The transmission of light depends whether the polarizers are aligned in parallel (maximum transmission) or perpendicular (minimum transmission) to each other.

Fig. 1: Various pieces of packing tape placed between a computer, and polarized sunglasses. (Image created by the author).

Now, we can take these two perpendicular polarizers and slide a piece of transparent tape  between them. Better yet, we slide a big mash-up of pieces of tape in between. What happens? Suddenly the polarizers fill with colour (Fig. 1 and 2). In fact, I encourage you to do this right now! You might not have polarizing sheets lying nearby, but if you have polarized sunglasses and a computer screen, you can do it. Most computers produce polarized light, and your sunglasses act as the second polarizer. Just zoom your computer screen into some white section of this article, increase the brightness, throw some pieces of tape together, and look at them between your computer and polarized sunglasses (nearly all tape will work, but some work better than others). You should see a stained-glass window-like array of colours which changes as you rotate the tape. 

Fig. 2: A more involved piece of art by physicist Aaron Slepkov [5, p. 619]

What in the world is going on here? The tape demonstrates the phenomena of birefringence. When light passes through the back polarizer (or your computer screen), it has one polarization. Then the tape does something very neat, and rotates this polarization of light by some amount. Importantly, the amount by which the light is rotated depends on both the wavelength of the light, and the thickness of the tape. For example, in the centre of Fig. 2, we see a bright green section. The polarised light is rotated by just the right amount as it passes through the tape so that the resulting polarisation is perfectly aligned with the second polariser to pass through unchanged. Perhaps the red light, on the other hand, was rotated just enough to be completely cut out by the second polarizer. The amount that the light gets rotated depends on the thickness of the tape as well, meaning that places with more layers of tape will display different colors than places with fewer layers. By varying the number of layers, we can get a wide array of colours.

Now, how do birefringent materials rotate light? When light passes from one medium to another, the light refracts, and its direction changes as a result of a difference in index of refraction across the mediums. Some objects, like the tape, are birefringent, and due to their molecular structure, the index of refraction is different depending on the polarization of the light incident (2). When unpolarized light is passed through a birefringent object for a long enough time, the beam can split into two separate beams, each with perpendicular polarization. In many cases, the light does not travel for long enough in a birefringent material to fully split the incident beam. Instead, the different indices of refraction will create a phase shift in the two polarizations of light resulting in a change in the polarization of the exiting light. This often results in partially elliptically polarized light but can be approximated as a net rotation of the polarized light.

The world of birefringence is far and wide. This technique of viewing birefringent objects between two polarizers can be used to analyse stress patterns in plastic ( look at your plastic ruler between two polarizers) (3) and in geology (a number of rocks are birefringent) (4). Most importantly, we can create some beautiful pieces of art: birefringence is a fascinating concept to study..

Works Cited

1. Halliday D, Resnick R, Walker J. Fundamentals of Physics. 10th ed. Wiley; 2014. p. 997–998. ISBN 978-1-118-23061-9

2. Belendez A, Fernandez E, Frances J, Neipp C. Birefringence of cellotape: Jones representation and experimental analysis. European Journal of Physics. 2010;31(3):551-561.

doi:10.1088/0143-0807/31/3/012

3. Redner AS, Hoffman BR. Measuring residual stress in Transparent plastics. mddionline.com. 2017. https://www.mddionline.com/news/measuring-residual-stress-transparent-plastics

4. Alderton D. Other Silicates: The Al2SiO5 Polymorphs, Cordierite, Staurolite, Epidote, Chlorite and Serpentine. Encyclopedia of Geology. 2nd ed. Academic Press; 2021. p. 368-381. ISBN 9780081029091. https://doi.org/10.1016/B978-0-08-102908-4.00186-7 

5. Slepkov AD. Painting in polarization. American Journal of Physics. 2022; 90 (617): 617-624. https://doi.org/10.1119/5.0087800

Author: 🇵🇭 Harvey Sapigao

In celebration of World Quantum Day 2023, the jIAPS Article of the Month is quantum-themed.

———-

“Oh, so you study physics. What are you going to be? A physician?”

We often get this comment after telling people our degree. The confusion is understandable; ‘physician’ and ‘physicist’ do sound alike, have similar etymologies (both coming from the Latin word ‘physica’), and might as well mean one or the other in a parallel universe. But I once got a remark that I was going to be a psychologist, which I thought was a bit of a stretch. 

We often think concepts in physics are so far removed from psychology, other than the fact that working with the Schrodinger equation can make our brains hurt. But physics, especially in the realm of quantum mechanics, is actually helping explain things about our minds, and these insights might also help us with our own mental well-being.

The obvious connection between quantum mechanics and psychology is that our brains are composed of matter, and matter, on the subatomic level, behaves quantum mechanically. Neurons typically communicate by passing ions to one another (1). The channels through which these ions pass are only fractions of nanometers thick – small enough for quantum effects to occur (2). In fact, the transmission of ions has shown to be compatible with quantum tunneling models (3). This is a stark departure from the classical notion that ions simply pass through channels like balls through tubes.

But the contribution of quantum mechanics goes far beyond neurons and ions. We now know that elementary particles don’t just strictly behave as particles; they also behave as waves. And just as there is a wave-particle duality in quantum mechanics, there is an analogous paradox in psychology: the mind-brain duality (also known as the mind-body duality, or ‘bodymind’) (4).

When classical physics was the only version of reality we knew, the idea of the mind and the brain was that of a dualism, not duality (5). That is, the mind and the brain were thought to be two completely different things. The thoughts, feelings, experiences, and everything that cannot be represented by matter were separated from those that can. ‘Mental’ states were separated from ‘physical’ states much like how waves were separated from particles.

René Descartes popularized this dualism and was named after him (5). Cartesian dualism is a seemingly innocuous – even helpful – dichotomy, but it has actually contributed to the mental health stigma we are facing to this day (6,7). This dualism has contributed to the notion that mental problems are very different from physical ones, and so, in many countries still, psychiatric hospitals are separated from general hospitals (7). Throughout history, treatments for the mentally ill have often been very different from those for the physically ill, and even the phrase ‘mentally ill’ has a negative connotation (7,8). Cartesian dualism has also contributed to the common misconception that mental issues are “all in the mind” and can be treated with having the right mindset (6).

Quantum mechanics brought the idea that reality wasn’t as cut and dry as we thought it was. Atoms can be in a superposition of states: a wave and a particle. And so, duality was born. This helped us understand that mental health might be both a mental and a physical affair; a duality – not dualism – of the mind and the brain.

Needless to say, mental health is not the same as physical health. But the two are not so dissimilar that treatments for the former were once thought of as witchcraft and the latter as medical science, as was the case in the time of Descartes (9). Indeed, research suggests that psychiatric drugs are just as effective in treating mental illnesses as other medical drugs are in treating physical illnesses (10). However, since mental health is also dependent on the mind, other treatments such as cognitive-behavioral therapy (CBT), or talk therapy, also work (11). Psychiatric drugs address the problem in a physical sense while talk therapy addresses it in a mental sense, and yet one can be as effective as the other.

***

We know that the physical aspect (the brain) is made of matter (quite literally, the gray and white matter), but what exactly is the mental aspect (the mind)?

Elementary particles – electrons, photons, quarks, etc. – are the smallest units of matter, and in quantum mechanics they come in discrete units called quanta. In psychology, a similar concept arises: the qualia (12). Qualia describes a unit of subjective experience; it is the color yellow as perceived by our eyes; the note A-flat as perceived by our ears; the feeling of tingles as perceived by our skin. That’s qualia. And whether or not we like the look of yellow, or the sound of A-flat, or the sensation of tingles, is also qualia. Put together, these hints of experiences make up our consciousness, and our consciousness, in essence, is what we have been calling the mind. Indeed, qualia make up the mind just as quanta (elementary particles) make up the brain, and that the mind-brain is the quality and quantity of a human.

An important feature of consciousness is that it is personal. It is based on our own subjective experiences; we all see colors, hear notes, feel sensations, differently. Moreover, we experience things in only one way: our own. Therefore, equating one’s own experiences to those of another is not only futile, but also impossible.

But some argue that consciousness is merely the result of matter interacting with one another; they are simply the result of neurons and ions playing around. There are, of course, conscious processes that can be mapped out in the brain; for example, the prefrontal cortex – the part of the brain near the forehead – activates whenever we act in a conscious manner, such as speaking, as opposed to, say, snoring while sleeping (13,14). But how consciousness emerges from the ‘lighting up’ of those neurons is still a mystery.

Consider a classic example in philosophy: the ‘chairness’ of a chair. Different materials, such as wood, metal, and plastic, can be used to make a chair. When these materials meet our rudimentary standard of what a chair is — something that can be sat on, have legs, and stand on its own — they become a chair. These properties emerge as special characteristics of a chair, but are not intrinsic to the wood, metal, or plastic from which the chair is made. Only when these materials are arranged in a particular way do they acquire these properties; wood, for example, cannot be sat on, have legs, and stand on its own unless it is assembled as a chair. These properties — the chairness of a chair — seem to appear out of nowhere, beyond the physicality of the materials.

Consciousness seems to appear out of nowhere, too. These networks of neurons are intertwined in a way that makes consciousness emerge. Consciousness is not a property of a bunch of neurons, just as chairness is not a property of a bunch of wood. But arrange them like a live brain, and consciousness emerges.

The idea that we are nothing more than the result of interactions of matter is called ‘materialism’ (15). Materialists think that consciousness is an illusion, as is the chairness of a chair. This view was especially popular before quantum mechanics, when all we knew about the world was in terms of balls revolving around bigger balls (whether that be electrons revolving around the nucleus or planets revolving around the sun).

Now, some find materialism difficult to accept. As we now know, funky stuff happens in the quantum realm, and most, if not all, cannot be expressed in terms of definite, intact balls. If the materialists are right, what would then be the difference between an alive and a dead person, if all there is to them are essentially balls? How did a bunch of mindless, zombie atoms conspire to create a brain-full, alive-and-kicking human being? Philosopher William Luijpen mentioned a contradiction among materialists: they philosophize and classify themselves as the same with chairs and tables, yet philosophizing and classifying are actions chairs and tables cannot do (16).

Still, what consciousness really is (and if it even exists) remains contentious in the fields of psychology, philosophy, and more recently, artificial intelligence. But one of the most commonly accepted views today is that consciousness coexists with matter, and we cannot be human without having one or the other. If we lose consciousness forever, we become corpses (a.k.a dead), and if we lose matter forever, we become, in paranormal terms, a ‘soul’* (a.k.a dead).

***

One of the interpretations of quantum mechanics, the von Neumann-Wigner Interpretation, assumes that consciousness exists. John von Neumann and Eugene Wigner’s interpretation was inspired by the earlier Copenhagen Interpretation.

Naturally, in a quantum mechanics sense, the wave/particle’s state is a cloud of probability; the state is indefinite, having no exact value. Its state can only be described in a probabilistic curve based on its wave function. But upon measurement, the wave/particle instantaneously evolves into a single state; the wave function ‘collapses’ and becomes a single, definite value. According to the Copenhagen Interpretation, the mere act of measuring alters the wave/particle’s state from its probabilistic nature to an exact and determined value (17).

However, the Copenhagen Interpretation did not address what constitutes a measurement, a conundrum known as ‘the measurement problem.’ To solve this problem, von Neumann injects into it the idea of consciousness, where he postulated that a conscious being (i.e. humans) must be doing the measuring (18). According to him, every state exists indefinitely in a soup of superposition and quantum probabilities until they encounter a human, which collapses them into single states. The states then cascade like dominoes, eventually creating a definite reality which we call the universe.

Von Neumann determined three processes at play. The first, called ‘process 1’ or ‘the Heisenberg choice,’ is the conscious choice, or more familiarly called the free will, of the observer on how to act or go about acting. It is the process that collapses probability into certainty. But before states collapse (i.e. undergo process 1), they first exist in states of clouds of probability, a process von Neumann called ‘process 2.’ Process 2 generates and superposes virtually all possible outcomes of the universe. The third process, called ‘process 3’ or ‘Dirac choice,’ is the outcome that arises from processes 1 and 2. Process 3 is the reality as a result of the clouds of probability (process 2) being collapsed by humans (process 1).

It is worth noting that a measurement is not limited to looking or observing or using a microscope. Measurement, as in the context of process 1, occurs at a more fundamental level, affecting a bunch of neurons and ions first before affecting bigger devices, such as the eyes, then the microscope, and so on (it cascades like dominoes).

What’s interesting about the von Neumann-Wigner interpretation is that it assumes reality arises as a result of consciousness. It puts us as the agents of the universe; one that makes things happen as opposed to one that happens as a result of. It’s not that we are the consequence of the universe, but that our conscious decisions create consequences in the universe. If the von Neumann-Wigner interpretation is true, it can have profound implications on the way we view life.

***

Wave-particle and mind-brain. Qualia and quanta. Consciousness and matter. All convenient parallelisms in the world of psychology and physics. But how do these apply to our own mental well-being? The paper “Quantum Physics in Neuroscience and Psychology: A Neurophysical Model of Mind–Brain Interaction” by Jeffrey Schwartz, Henry Stapp, and Mario Beauregard attempts to explain how mental effort manifests into the world around us, borrowing concepts from quantum mechanics in describing the mind-brain interaction (19).

The paper first points out the problem that arises when we only look at psychology through the classical (deterministic) lens, which assumes that our consciousness is merely a by-product of the neurons from which our brains are made, and therefore has no ability to affect the physical world. Consciousness can be thought of as a hologram, where it is there but cannot move objects around it, and is thus an illusion.

Yet multiple studies have shown that consciousness does affect the physical world. For example, cognitive-behavioral therapy (CBT) has been highly effective in treating mental illnesses such as unipolar depression, generalized anxiety disorder, and panic disorder (20). Neuroimaging has revealed that significant changes in the brain occur after CBT sessions of patients with phobic disorders (21). People with obsessive-compulsive disorders have even been able to reduce their habits through willful action (22). This phenomenon has become an active area of research since the 1990s and has been termed ‘self-directed neuroplasticity’ (22).

Self-directed neuroplasticity is the ability to alter the neuronal circuitry of our brains through willful effort, allowing us to rewire our brains to match the way we want to think. Because our brains are plastic and malleable, and because consciousness can affect the physical world, controlling our consciousness has a direct consequence in the universe – a phenomenon that couldn’t be explained by the classical model of physics.

The paper then goes on to argue that the mind-brain interaction is explained by the processes mentioned in the von Neumann-Wigner interpretation. Process 1, according to them, “describes an interaction between a person’s stream of consciousness, described in mentalistic terms, and an activity in their brain, described in physical terms.” That is, process 1 bridges the gap between the mental mind and the physical brain; it facilitates the interaction between the mind and the brain.

Process 1 is further divided into two: the passive and active process 1. The passive version, as the name suggests, does not require much conscious thought, while the active version requires conscious effort. It is akin to voluntary and involuntary actions of muscles; heart contraction is involuntary (and thus is passive), whereas weight-lifting is voluntary (and thus is active).

The active and passive processes also differ in a variable called ‘attention density’ – the amount of attention exerted in a period of time. The authors described attention density as “the rapidity of process 1 events.” In other words, it is the number of measurements done per time interval (recall that process 1 is the act of measuring by a conscious being). The active process requires a higher attention density compared to the passive process; the active process measures a quantum system much more frequently than the passive process.

A quantum system, if left unchecked for a period of time, will evolve into a superposition. For example, if the wave function of the quantum system, at t = 0 ns, gives a 100% probability to ‘yes’ and 0% to ‘no’, after some time, say 1 ns, the quantum system will evolve into 90% ‘yes’ and 10% ‘no’. After 2 ns, the system becomes 80% ‘yes’ and 20% ‘no’, and so on. This is how quantum systems evolve through time, only that it has no pattern; the ‘yes’ and ‘no’ probabilities oscillate unpredictably, albeit gradually, over time.

Now, if we measure a quantum system, it will collapse into a single state; the system collapses into 100% ‘yes’ and 0% ‘no.’ If we do this multiple times, the system will collapse every time. If we do this rapidly and much more frequently, the quantum system will not have enough time to evolve into a superposition; the system will ‘freeze’ into a 100% ‘yes’ and 0% ‘no’ so long as we keep measuring it rapidly. This effect is called the quantum Zeno effect (23).

The active process, according to the authors, produces the quantum Zeno effect. Since the active process has high attention density (high measurement frequency), it produces the quantum Zeno effect in a quantum system. Therefore, if we exert mental effort (which increases attention density and thus invokes the active process), we can essentially control a quantum system, and consequently whatever is connected to that system.

The implication of this is that we are, indeed, agents of the universe rather than mere products of it. We have control over our actions and we have the freedom to choose. This realization can be immediately beneficial to the nihilistic, but those who are struggling with other mental issues can also learn from the paper. If we are willing to do something (such as wanting to get better, or, at least, believing that we can), it has a chance of materializing, which is much less bleak than not having control at all.

The authors explicitly state this implication, saying that the importance of a patient’s willingness and commitment to get treated is essential. They said that “it takes effort for people to achieve therapeutic results. That is because it requires a redirection of the brain’s resources away from lower level limbic responses and toward higher level prefrontal functions—and this does not happen passively.” Moreover, “clinical success is jeopardized by a belief on the part of either therapists or patients that their mental effort is an illusion or a misconception.”

Of course, the paper hinges on the fact that the Von Neumann-Wigner interpretation must be true for their conclusions to be true. But, if I may be philosophical for a bit (being careful not to mistake ‘physicists’ for ‘philosophers’), I find it comforting to think there is an inkling of a chance that we live in a universe where we have authority over our choices; where we have free will; where our lives are not set in stone.

If consciousness is an illusion and the universe is deterministic, what then separates us from algorithms and Twitter bots and Dall-E? What laws of physics enabled us to contemplate and ruminate and have existential crises? What is stopping us from becoming just cogs in a machine?

If that really is the case, I’m glad we don’t know. It leaves room for imagination, for thoughts, for feelings, for opinions, and for beliefs. And even if some think opinions and beliefs disparage humans more than enhance them, that in itself is an opinion or belief which they hold. In a way, we are living in a superposition, and we can only guess our states. But not knowing is what comforts me. It is the bliss of ignorance. And this is what I choose.

* This is only for representational purposes, as the idea of a soul contradicts the mind-brain duality. According to the theory, consciousness cannot exist by itself, so a soul should not exist on its own (and caught-on-camera “ghost” videos are only pareidolias). The belief that they do exist is called “spiritualism,” which Luijpen thought was as flawed as materialism.

References

1. Lall S. How do neurons communicate (so quickly)? [Online] MIT McGovern Institute. MIT; Available from: https://mcgovern.mit.edu/2019/02/28/ask-the-brain-how-do-neurons-communicate/ [Accessed: 8thDecember2022] 
2. Cataldi M, Perez-Reyes E, Tsien RW. Differences in apparent pore sizes of low and high voltage-activated ca2+ channels. Journal of Biological Chemistry. [Online] 2002;277(48): 45969–45976. Available from: doi:10.1074/jbc.m203922200 
3. Nawafleh S, Qaswal AB, Alali O, Zayed FM, Al-Azzam AM, Al-Kharouf K, et al. Quantum mechanical aspects in the pathophysiology of neuropathic pain. Brain Sciences. [Online] 2022;12(5): 658. Available from: doi:10.3390/brainsci12050658 
4. Eastman T. Duality without dualism – California State University, Sacramento. [Online] Available from: https://www.csus.edu/cpns/library/te_dwd.pdf [Accessed: 8thDecember2022] 
5. Robinson H. Dualism. [Online] Stanford Encyclopedia of Philosophy. Stanford University; Available from: https://plato.stanford.edu/entries/dualism/#MinBodHisDua [Accessed: 8thDecember2022] 
6. Mehta N. Mind-body dualism: A critique from a health perspectivefnx08. Mens Sana Monographs. [Online] 2011;9(1): 202. Available from: doi:10.4103/0973-1229.77436 
7. Latoo J, Mistry M, Alabdulla M, Wadoo O, Jan F, Munshi T, et al. Mental health stigma: The role of dualism, uncertainty, causation and treatability. General Psychiatry. [Online] 2021;34(4). Available from: doi:10.1136/gpsych-2021-100498 
8. Talking about mental health. [Online] Mental Health Foundation. Available from: https://www.mentalhealth.org.uk/explore-mental-health/a-z-topics/talking-about-mental-health [Accessed: 8thDecember2022] 
9. Mental illness in the 16th and 17th centuries. [Online] Historic England. Available from: https://historicengland.org.uk/research/inclusive-heritage/disability-history/1485-1660/mental-illness-in-the-16th-and-17th-centuries/ [Accessed: 8thDecember2022]
10. Leucht S, Hierl S, Kissling W, Dold M, Davis JM. Putting the efficacy of psychiatric and general medicine medication into perspective: Review of Meta-Analyses. British Journal of Psychiatry. [Online] 2012;200(2): 97–106. Available from: doi:10.1192/bjp.bp.111.096594 
11. Hofmann SG, Asnaani A, Vonk IJ, Sawyer AT, Fang A. The efficacy of cognitive behavioral therapy: A review of meta-analyses. Cognitive Therapy and Research. [Online] 2012;36(5): 427–440. Available from: doi:10.1007/s10608-012-9476-1 
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Author: Zlatan Vasović

Have you ever thought that physics is missing its international day? A new initiative by quantum scientists around the world could just change that— an initiative to celebrate April 14 as World Quantum Day. Its main goal is to promote quantum science and technology around the world.

The importance of quantum has been growing, and so has the need to promote the understanding and achievements of quantum science. The Nobel Prize in Physics 2022 confirms this—it was awarded to Anton Zeilinger, Alain Aspect, and John F. Clauser for their work on tackling fundamental questions of quantum mechanics. This gives us a special occasion to celebrate the fundamentals of quantum science, its applications, and its possible impact on our society.

World Quantum Day originally started as a decentralized initiative by scientists around the world. It was launched on April 14, 2021, as the countdown towards the first celebration on April 14, 2022. The date was chosen as a reference to 4.14, the rounded first digits of Planck’s constant: 4.13567×10-15 eV·s.

The first World Quantum Day was celebrated in 2022 through 200+ events in 40+ countries. The events promoted all domains of quantum science, as well as its history, foundations, applications, and philosophical and societal implications. There are both online and in-person events, meaning that you can take part wherever you are in the world. 

Now the second celebration is just around the corner. It’s set for April 14, 2023, but the events don’t have to be on that exact date. You can find more information on how to engage at https://worldquantumday.org/. 

Let’s celebrate World Quantum Day!

Editor’s Note – jIAPS is celebrating World Quantum Day too: the April photo competition is Quantum themed and is listed on the World Quantum Day website. Enter your quantum or physics-themed photos by emailing them to us at jiaps@iaps.info.

Author: Chukwuma Anoruo, University of Nigeria

Illustrated by Harvey Sapigao

Chukwuma Anoruo is a postgraduate student of the University of Nigeria. He is the lead author of a recent study (1) which found that the anomalies in total electron content (TEC) in the African region ionosphere during the initial and recovery stages of geomagnetic storms are more pronounced in the low latitude region. This study showed that the physics of the ionosphere at mid- and low-latitudes of the African region is needed to understand the rate of change of TEC. This was demonstrated using the example of the geomagnetic storm on 19th February 2014. Anoruo analysed storm-time changes from global navigation satellite system (GNSS) data using the African Geodetic Reference Frame (AFREF) network.

Anoruo’s career started with a BS in Physics and MS in ‘Physics of the Lower Atmosphere’, where he majored in aerosols, carbon dioxide measurements and air quality monitoring. He describes the experience as ‘excellent’ and enjoyed completing field work exercises as well as contributing to the group review of the Intercontinental Panel of Climate Change.

Anoruo describes his experience of being a PhD student during the global pandemic:

‘I started as a PhD student in 2018 at the University of Nigeria, Nsukka. During the early stages of my doctoral program, I started to read more manuscripts, textbooks, attend conferences, workshops and engage in space weather discussions through Twitter and other social media. I experienced challenges, including the struggle to obtain funding to complete a PhD. One particular challenge was that I was given accommodation far from the University campus. 

The COVID-19 pandemic made an impact on the lifestyle of Early-Career Researchers (ECRs). The situation of ECRs in Nigeria was already difficult before the pandemic, due to lack of opportunities and funding. During the pandemic, the Nigerian government enforced a stay-at-home order, intended to keep people safe. The restrictions resulted in the closure of the universities and research centres, so I had to work from home. Being housebound during the pandemic interfered with my ability to focus on my thesis. I lost touch with my supervisors and experienced inertia.

There are numerous issues that developing countries like Nigeria have in common and that could worsen the impact of the pandemic. How can people without access to clean water be expected to wash their hands? How can people in an overcrowded environment practice social distancing? How can people mostly without stable and regulated electric power work from home? These major challenges — mainly the lack of access to electric power — confronted me. When I started to work from home, I only had access to 24% of the normal power supply. The lack of electrical power caused delays in communication with collaborators by email and video call.

Even though I experienced these challenges, I found ways to maintain my physical and mental health. I adapted to a new routine, starting to exercise using my home environment and listening to, and sometimes playing, musical instruments.  When in-person events were cancelled, I attended virtual international conferences, workshops and communicated with senior scientists in Space Science.’

1. C. Anoruo et al. Front. Astron. Space Sci. (2022), 9, 947473
   https://www.frontiersin.org/articles/10.3389/fspas.2022.947473/full 

Adapted from:

Intern. Assoc. of Geomag. and Aeronomy Blogs (4th February 2022). Available at: https://iaga-aiga.blogspot.com/2022/02/doctoral-and-postdoctoral-low-benefits.html?m=1 [Accessed 20th January 2023]

PAGES Early-Career Network Blogs (11th June, 2020) Available at: https://theearlypages.blogspot.com/2020/06/early-career-researchers-in-covid-19.html#anoruo [Accessed 20th January 2023]

Are you a research student? We’d like to hear from you – we’d be interested in receiving a summary of your research or your experiences as part of a research group. Just email jiaps@iaps.info or contact us on social media. 

🇺🇦 🇬🇧 Anastasiia Vasylchenkova, IPT national representative in the UK

This year in the United Kingdom, we had the first-ever National Selection for the International Physicists’ Tournament in tournament style. In previous years, the participants just had to submit a written report for selection. This year, it has been quite inspiring to have a national selection, as teams could experience all the joy and fun of physics fights. 

The International Physicists’ Tournament (IPT) is a competition which gathers university student teams from all around the world for a unique process of solving challenging problems in teams and defending their solutions at Physics Fights. From this year, the IPT is a major event under the umbrella of IAPS. More information is available via iptnet.info.

At the beginning of December, three teams arrived at the University College London (UCL) for the National Selection event. We had a University of Cambridge team, a UCL team and a joint team from UCL and Kings College London. 

The IPT is famous for thought-provoking problems for training research and debating skills of our participants. For example, the last report by the winning – Cambridge – team was about Dancing light problem. It states: “Put a membrane with a mirror over a speaker. Then project the reflection of a laser pointer over a screen. By driving the speaker with single or multiple frequencies you may observe lines and shapes projected on the screen. Given a closed trajectory in 2D of a single line, find the input on the speaker required to “paint” the line. Can you also “rotate” the line as you desire? Investigate the limitations.”

Other participants and jurors were pleased to watch experimental videos of the reporting team, listen to their hypotheses and outcomes, and have a discussion about different aspects of the physics behind the phenomena. 

We heartily appreciate the teams’ efforts in solving the IPT problems and dedicating their Sunday to participation in physics fights. We are also extremely grateful to our jury panel for working very hard in assessing teams’ performance. Last but not least, the IPT was supported by the Institute of Physics, in particular, London and South East Branch, and STEMM Global Scientific Society.

There are lots of opportunities to get involved with jIAPS – here we would like to recognise the incredible efforts of our top contributors so far this year. 

There is still chance to contribute to jIAPS, whether you would like to write an article, send a photo of an event you participated in, or help with graphic design – just email us at jiaps@iaps.info .

Congratulations to the following jIAPS Staff Members who have reached these milestones:

50 contributions: 

🇵🇭 Harvey Sapigao 

30 contributions:

🇯🇵 Muhammad Frassetia Lubis 

10 contributions:

🇲🇰 Evgenija Pandova 

🇲🇽 Fabiola Cañete

🇮🇳 Jeet Shannigrahi

🇮🇳 Noumish Hait

🇪🇸 Pedro Villalba González 

5 contributions:

🇳🇵Rabin Thapa

🇬🇧 Sophie Gresty

🇩🇴 Thara Caba 

🇷🇸 Zlatan Vasović

Author: 🇳🇵 Rabin Thapa, Dolpo Buddha Rural municipality, Dolpa

Rabin has shared his experiences of being a Science teacher in a mountainous region of Nepal with jIAPS:

After completing my Master’s degree in physics, I applied for the post of teacher of mathematics and science in Crystal Mountain School (CMS) which is located in upper Dolpa at an altitude of 4300 meters. Inside me, the answer to the question: ‘why did I apply for this professional vacancy as a late twenties Nepalese citizen , is still an unanswered conflict or chaos tumbling in a wave of thought whenever I close my eyes.

Passing through the physical interview process and orientation, I was ready for an hour flight from Kathmandu to Nepaljung, followed by two days road travel and three days uphill trek to the school. However, my plans were disrupted by a domestic flight cancellation. 

Vision Dolpo, an organization managing the seven months academic terms during summer with an ambition to uplift the local literacy potential, can be highly praised. During the six days’ journey, the pressure related to finance and socio economic fluctuation was clearly visible. Meanwhile, we reached our destination on 17th April. A day’s rest was scheduled to face altitude sickness before starting regular teaching on 19th April.

Considering the harsh geographical navigation of CMS coupled with the local living standard, the encounter of limited stationary, student’s uniforms, teaching resources, regular food and IT access was inevitable. In this context, everything apart from basic requirements had to be brought from the capital, to be able to conduct regular academic activity. These supplies were  transported from Dolpa’s district headquarters to the school’s location by mules and donkeys. In April, around hundred shacks of school material were on the way to our location. During dinnertime a few days after I arrived, I heard that Dolpo Buddha Rural Municipality was facing official blockage due to political turbulence, which resulted due to per-planned local elections announced by the government. Due to this blockage, whatever its cause, CMS’s administration had to face the scarcity of food for the staff. Most prominently, the 250 students who come to school here are struggling with availability of stationary, learning material, laboratory tools and uniforms. The stark reality, the real image of public education as experienced by me, is really heartbreaking. I can remember wishing that my heartache could be consoled and thinking of the passenger’s song entitled, “Survivor”.

After a long wait of three months, the supplies, including the stationary for the students, finally arrived. However, the staff, along with the administration team, had to overcome the challenge of continuing regular academic activities with limited resources. At a general meeting, I was assigned to initiate the lead in STEAM activities and upgrade the science laboratory. Selecting extracurricular projects was pivotal because I found that very few students in the school were interested in classical or analog projects. Consequently, to motivate interest in modern science and technology, we established a ‘Makers’ Club’. The annual projects selected were: the construction and installation of electric bell, execution of robotics design and designing a smart dustbin. Fifteen students initially enrolled in the ‘Makers’ Club’. In the ‘Maker’s Space’, we came to a mutual agreement with the students that all the members had to contribute two hours to the club every day after their regular class. 

These two hours of the school day are the most precious time for the students. They can explore a variety of engineering tools, through regular workshops where they are instructed in practical electronics, magnetism, wiring, working principle of switches, AC, DC, transformers, software coding, hardware and basic design principles, to name a few activities. Sometimes, the students became so enthused by their projects that we used to work for hours, even without sleeping. When all our annual projects were accomplished, after four months of hard work, we showed our finished products to the other students and we were able to attract more students to join the ‘Makers’ Club’. Now, at the altitude of 4100 m, in a remote mountainous region of Nepal, we have a self-made electric bell in operation; an inter-house robotic battle; and smart dustbins with software and hardware developed by the students. In our corner of the world, we are introducing modern science and technology to children in their regular learning environment, in a region where these scientific advances were unknown. 

Photo Credits: Rabin Thapa

Implications of Relativistic Effects on the Global Positioning System (GPS)

Raghav Sharma, BSc Physical Science with Electronics, University of Delhi

Abstract

Relativity has no obvious consequences in daily life, but one close look at the working of a GPS device is sufficient to highlight the enormous implications of relativistic effects on situations where velocity, gravity, and accuracy are involved. Clocks on a moving satellite do not appear to tick at the same intervals as clocks on Earth. This is especially problematic in high-accuracy systems like the GPS. Understanding the mathematical principles behind these effects allows for a derivation of precise offset values- adjustments that need to be made to satellite clocks to correct any time difference caused by relativity.

Introduction

The Global Positioning System (GPS) is a highly accurate, satellite-based positioning and navigation system.^[1] To maintain that accuracy, time-dilating relativistic effects arising from both the general and special theory of relativity need to be taken into account. This is achieved by adjusting the rates of onboard satellite clocks and incorporating mathematical corrections. This article explores time dilation effects on GPS and describes some calculations and adjustments that are made to account for them. The correction for special relativistic time dilation is derived in detail.

1. An Overview of Time-Dilation Effects

A handheld GPS receiver can determine the absolute position on the surface of the Earth to within 5 to 10 metres.^[1] Achieving a navigational accuracy of 5 metres requires knowing the onboard GPS satellite time to an accuracy of about 17 nanoseconds, which is the time taken by light to travel 5 metres. Because satellites are constantly moving with respect to the Earth-centred (approximately inertial) frame and are further away from the Earth’s gravitational well, one must consider time dilation caused by both special and general relativistic effects. If these effects were left uncompensated, navigational errors would accumulate at a rate in excess of 10 kilometres per day, rendering the system unusable within about 2 minutes.^[2] 

2. Special Relativity

GPS Satellites are not geosynchronous because that would limit coverage. They have a time period of about 12 hours (so that any satellite passes over the same location each day) and a corresponding orbital velocity of about 3874 m/s relative to the centre of the Earth.^[3]

According to the Special Theory of Relativity, moving clocks run slower.^[2] The time dilation amount is determined by Lorentz transformations. The time measured on-board the satellite is reduced by the Lorentz factor γ:

where τ_{Ground} and τ_{GPS} are time intervals measured on the Earth’s surface and by the satellite clock, respectively.

The derivation of the time by which satellite clocks lag behind surface clocks, Δτ, is given below: 

Using binomial expansion for small values of (v/c):

Taking v=3874 m/s and c=2.998×108m/s:

 For a time-interval of 1 day (86,400s) on the Earth’s surface:

Therefore, GPS clocks lose about 7μs a day due to special relativistic time dilation.

3. General Relativity

GPS satellites have an orbital altitude of 20,184 km measured from the surface.^[3] According to the General Theory of Relativity, a clock in a gravitational field runs slower. This effect is given by:

Where τ_0 is the time interval measured near a mass (i.e., in a gravitational well), and is the time interval measured far away from the mass. 

For small values of (M/r):

The clocks on the Earth’s surface are a distance of R_Earth=6378.1 km from the gravitational centre, so the time dilation with respect to GPS satellites is twofold. It is stated without proof that due to general relativistic time dilation effects, clocks onboard the satellites gain about 45μs per day, with respect to ground-based clocks.^[1]

4. Error Correction

The combination of general and special relativistic time dilation means that GPS clocks gain about 38μs a day. As stated before, the desired accuracy can be as high as 17 nanoseconds. Thus, it is crucial to correct any time difference. 

A time offset of 38μs corresponds with a fractional change of +4.465×10^-10, i.e. the satellite clocks need to be slowed down by this fraction. The fundamental L-band frequency produced by the atomic clocks on-board is 10.23 MHz. This needs to be offset by the aforementioned fraction. Therefore, the actual frequency of the GPS clocks is set to 10.22999999543 MHz before launch.^[3-4]

The variation in these changes due to the eccentricity (deviation from circularity) of the satellite orbit also needs to be taken care of. Built-in microcomputers used in GPS receivers help in any additional timing calculations required using satellite-provided data.^[1]

Conclusion

Relativity dictates that clocks aboard GPS satellites do not tick at the same rate as those on the Earth. Both general and special relativistic time dilation effects are at play. Neglecting to adjust for these would render GPS useless in a few minutes. Correcting them involves giving the onboard atomic clocks a slight offset in frequency, so that they may appear to run at the same rate as ground-based clocks. This correction is one of many needed to maintain a navigational accuracy of up to a few metres.

References:

1. Pogge, Richard W. (2017): Real-World Relativity: The GPS Navigation System
2. Will, Clifford M.: Einstein’s Relativity and Everyday Life
3. Nelson, Robert A. (1999): The Global Positioning System- A National Resource
4. Oxley, Alan (2017): Uncertainties in GPS Positioning- A Mathematical Discourse, Pages 71-80