It cannot be said, with any stretch of the imagination, that I am afflicted with green fingers. In fact, many years ago when I told my friends about my gardening attempts, they would burst out laughing. So, for years, prior to being presented with the opportunity to employ a gardener, I would think of that place outside my backdoor as a tortured garden. It is challenging to have a nice garden in a water scarce country.
So, why I decided to venture into this direction again, I don’t know. But it is fun, sort of.
I decided to harvest the pips of an overripe tomato and put them in some soil. Amazingly enough, they germinated. As they got bigger, I transferred them to individual containers. Now they are starting to become big enough to put into a big pot where they can stay until they would (hopefully) produce tomatoes.
I also had a garlic pod that started to look a bit sad. Although I like garlic in my food, I don’t seem to use it at a fast enough rate. So the garlic does not last. The thing made it quite clear that it wishes to burst forth and … grow. So, I relented and planted the thing. Now you wouldn’t believe just how must life there is in that pod. It sprouted leaves, all bunched together, like there’s no tomorrow. Soon I’ll have to find a bigger container and separate the thing into different pods, I guess.
Anyway, it would be a proud day, some time in the hopefully not too distant future, if I can harvest my own tomatoes and garlic and prepare some dish with them. It would mark a personal triumph, but I guess I still would not tell my friends, lest they laugh at me again.
South Africa has the dubious honour to be among the top ten countries in the world with the highest number of confirmed COVID-19 cases. Of these ten countries, South Africa has the highest rate of daily increase in cases, over 4%.
Why? Perhaps one can blame the existing culture of disdain for the government’s regulations. It doesn’t matter that the government is trying to impose regulations to curb the spread of the virus. People ignore it and try to life as they like. One can understand why the government has lost it credibility looking at the recent history of corruption, state capture, and general incompetence.
I’m a scientist and not a politician. So I don’t want to discuss politics. Any reasonable person that sees the statistics can decide for themselves that it makes sense to isolate oneself as far as possible. So, what the government is trying to do makes sense, even if it is sometimes a bit too little too late.
The bottom line is, here I’m sitting in my house like a hermit. The hermitic existence is not so bad. The idea of living as a hermit has been part of western culture for centuries. It is intend to improve spiritual growth. I guess, it very much depends on the kind of person that you are. Not everybody can handle such seclusion for an extended period of time.
As a theoretical physicist, one can perhaps take some inspiration from Charles Hermite, whose last name sounds like hermit. He was a French mathematician who made significant contributions that are still widely used in quantum mechanics, among other fields. For example, a Hermitian operator is one that equals it Hermitian adjoint. It always has real eigenvalues. All physical states are represented by Hermitian operators
It this sound like twaddle to you. Don’t worry. What I’m try to get at is that if you currently also experience a “Hermitian “existence (as opposed a hermetic existence), then you can know that you are a real (valued) physical person. (Haha – just kidding. Perhaps only the mathematically inclined would find that funny.)
That may sound a little cannibalistic. Of course, if I added the word “apple” at the end (as you probably guessed) then it would sound less gruesome, but then it would also lose its appeal.
I could also have said “eating a Granny Smith,” but apart from the grammatical awkwardness, I don’t like Granny Smith apples much. I use to when I was younger, but these days they are just too sour for my taste. They are good for baking I hear. Not that I’ve ever baked apple pie.
The one’s I like most are Pink Lady, Royal Gala, and Fiji apples. Golden Delicious is also nice if they are properly ripened, but the shops tend to sell them when they are still very green. Then they are not so nice.
I mostly just eat them fresh. They are very helpful to combat heart burn. At my age that becomes a constant irritation. Instead of using some medication to control heart burn, I prefer to do that by my diet. So, I stay away from those things that tend to give me heart burn. In my case those are spicy food, breads and buttery pastry. Then I have an apple a day. That keeps the doctor away, as they say.
Everything is no more or less in place to discuss one of the most enigmatic phenomena found in quantum mechanics: entanglement. It is sometimes called the quintessential property of quantum mechanics.
We have discussed the fact that quantum mechanics introduces the concept of discrete entities that carry full sets of degrees of freedom, and which I called partites. Then we learned about the paradox introduced by Einstein, Podolski and Rosen (EPR) and how it led to the understanding that nature does not have a unique reality. Although it also allows that interactions could be nonlocal, we saw that such non-locality is not in agreement with our understanding of special relativity. The final ingredient that we need to explain quantum entanglement is the concept of a superposition. We can deal with that here.
The term superposition is a fancy way of saying that we are adding up things. Superpositions are also found in classical optics. There, one can observe interference effects when two waves are superimposed (added on top of each other at the same location). What makes the situation in quantum mechanics different is that the things that are added up in a quantum superposition can consist of multiple partites (multiple combinations of discrete entities) and these partites (discrete entities) do not have to be at the same location. Since each entity carries unique properties, as described in terms of the full set of degrees of freedom, the different terms in the quantum superposition gives complete descriptions of the state in terms of the set of discrete entities that they contain.
Each the terms in the superposition can now be seen as a unique reality. The fact there are more than one term in the superposition, implies that there are multiple realities, just like the EPR paradox showed us. One can use the many-world interpretation to try to understand what this means.
There are now different effects that these superpositions can produce. In some cases one can factorize the superposition so that it becomes the product of separate superpositions for each of the individual partites. In such a case one would call the state described by the superposition as being separable. If such a state cannot be factorized in this way, the state is said to be entangled.
What is the effect of a state being entangled? It implies that there are quantum correlations among the different entities in the terms. These correlations will show up when we make measurements of the properties of the partites. Due to the superposition, a measurement of just one of these partites will give us a range of possible results depending on which term in the superposition ends up in our measurement. On the other hand, if we measure the properties of two or more of the partites, we find that their properties are always correlated. This correlation only shows up when the state is entangled.
Some people think that one can use this correlation the communicate instantaneously between such partites if they are placed at different locations that are far apart. However, as we explained before, such instantaneous communication is not possible.
This discussion may be rather abstract. So, let try to make it a bit simpler with a simple example. Say that we form a superposition where each term contains two partites (two discrete entities). In our superposition, we only have two terms and the properties of the partities can be one of only two configurations. So we can represent our state as A(1) B(2) + A(2) B(1). Here A and B represent the identities of the partites and (1) and (2) represent their properties. When I only measure A, I will get either (1) or (2) with equal probability. However, when I measure both A and B, I will either get (1) for A and (2) for B or (2) for A and (1) for B. In other words, in each set of measurements, the two partites will have the opposite properties, and this result is obtained regardless of how far apart these partites are located.
The phenomenon of quantum entanglement has been observed experimental many times. Even though it is counterintuitive, it is a fact of nature. So, this is just one of those things that we need to accept. At least, we can understand it in terms of all the concepts that we have learned so far. Therefore, it does not need to be mysterious.
Recently, I heard somebody talking on the radio about ways to start a day with positive energy. The person suggested all sorts of things, ranging from the things to eat or not to eat, the kinds of exercises to do and also even meditation. It occurred to me how fortunate I am that I don’t need to waste all that time on getting positive energy. When I wake up and I ask myself “what am I going to do today?” The answers is “physics!!!” and there I get all the positive energy that I need. It is my profession, my purpose and my passion.
Then I read the lamentations of Peter Woit in a blog post on the job situation in theoretical high energy physics. So, while it may be great to have a passion for physics, it is not a given that one can make it your profession. Indeed, I can remember that for as long as I’ve been in this field, the job situation was challenging.
Part of the problem is the way that physics as a profession is being practiced. One typically starts as a student studying physics, but what are the career expectations? Most physics students apparently expect to become physics professors at universities. Well, if you look at the number of students compared to the number of faculty positions in physics, then it is obvious that such expectations are quite unreasonable. Moreover, if every physics professor produces scores of physics PhD’s during his or her career, then obviously there would be a huge oversupply of physics PhD to replace that professor.
So where do these PhD’s go to work? First they become postdocs. The ideal postdoc is a person that basically runs the research program for a professor. They come up with the ideas of what to investigate and they even supervise the professor’s PhD students. But what are the professors doing then? They travel and give talks, raising their profile, building their networks, and increasing their impact. Some of them don’t even touch any research. It’s all about fame and glory. The postdocs basically become cheap labor to produce the content on which these professors are riding their ego trips. More than once, when I’ve asked such “eminent researchers” questions after their talks at conferences, I’ve discovered that they don’t really understand what they are talking about.
So what can be done? Firstly, the poor students studying physics need to understand this situation and be realistic about their expectations. Other career choices include teaching (in schools, not universities) or industry. The latter represents the idea of an “industrial physicist.” However, in this case there is a different form of competition. The industry is better geared for engineers, for obvious reasons.
Another thing. When you decide to do physics, please do it for the right reasons. If physics is you passion and will remain your passion for the rest of your life, by all means proceed. Somehow you’ll find a way to live out your passion. But, if you want to do physics because you want to show off how bright you are, then rather join Mensa and leave physics to those that are passionate about physics. And, if you want to do physics because you want to be famous, like Einstein and those guys, rather consider a career as a rock star or a movie star. Very few physicists ever become really famous, contrary to what they may think.