PhD Physics
Accelerator physics, photocathodes, field-enhancement. tunneling spectroscopy, superconductivity
One of the common questions or comments we get on PF is the claim that classical physics or classical mechanics (i.e. Newton’s laws, etc.) is wrong because it has been superseded by Special Relativity (SR) and General Relativity (GR), and/or Quantum Mechanics (QM). Such claims are typically made by either a student who barely learned…
We frequently get questions such as these: “What is energy?” “What are Cooper Pairs?” “What is conservation of momentum?” etc…etc. And the persons who asked such questions didn’t bother to explain the context of the question, what exactly did he/she wanted to know, and didn’t reveal the level of education that he/she could understand. While…
This is a compilation of my blog entry on this singular “project” to change the way we conduct the introductory physics laboratory in most US universities. I think we are missing a tremendous opportunity to educate a general audience on how we acquire and learn something in physics, and how we analyze something that we…
I mentioned in an earlier Insight what I think are the most important things you can learn by being on Physics Forums. This time, I tackle the question of what I think is the most important thing I learned in becoming a physicist. I get asked that question frequently. Whenever I do an outreach project…
During and even after the recent US election campaign, there were numerous reports of fake news, made-up news, and other kinds of news that were deemed either outright fabrication or inaccurate or incomplete reporting of something to skewer it into one point of view or another. While the outright-fabricated news can easily be spotted eventually,…
Key points: Quantum mechanics (QM) is often perceived as difficult, especially by non-physicists. The difficulty lies in the conceptual foundation of QM, as it doesn’t connect well with classical understanding. Unlike other areas of physics, there’s no direct continuity between classical concepts and QM. While the conceptual understanding is challenging, the mathematical formulation of QM…
I posted this elsewhere (on my personal blog), and someone mentioned that maybe it might also be useful here on PF. So I’m reproducing the entire entry here in case it might make a difference. This is essentially a “sequel” to my earlier essay on “So I am Your Academic Advisor“. My aim in writing…
I have seen this question being asked frequently on here. A lot of students have a bit of an issue in understanding why, if an electron is placed in a field with potential V, that the energy gain after going through the field is always eV, no matter how far away it has to move….
This is not about seeing an electron, but rather, the notion that seeing something with our eyes is the end-all requirement for the validity of anything. I will show that our human eye, as a light detector, is NOT a very good detector at all in many aspects, and thus, using it as the standard…
This question appears often because it has been shown that in a normal, dispersive solid such as glass, the speed of light is slower than it is in a vacuum. This FAQ will strictly deal with that scenario only and will not address light transport in anomalous medium, atomic vapor, metals, etc., and will only…
This question has popped up many times. So here is an attempt to address it. To answer this question at the elementary level, a number of assumptions will be made, which will become obvious later on. Still, at this point, we will simply deal with objects with spherical symmetry and no complicated mass distribution. In…
Introduction My feelings on people who think that imagination is more important than knowledge are well-known. These people simply are parroting Einstein’s phrase without understanding the context and implications. To prove that, I will cite two specific examples that I’ve encountered personally. These either came to me via direct contact with the person who made…
One of the most spectacular theoretical descriptions that Einstein had ever produced is the corpuscular nature of light that he used in his 1905 photoelectric effect paper. In fact, there have been arguments put forth that of all of his 1905 papers, the one proposing this model for light is what is truly most revolutionary,…
Do photons have mass? The quick answer: NO. However, this is where it gets a bit confusing for most people. This is because in physics, there are several ways to define and measure a quantity that we call “mass”. Now, it doesn’t create any confusion among physicists because we tend to know in what context…
It is no secret to anyone who has read my posts in this forum for a while that I do not like Wikipedia. I think that there’s a fundamental flaw with the whole concept and philosophy of it. While I think that it may be useful to many who need a quick lookup for something,…
One of the common misconceptions about the Heisenberg Uncertainty Principle (HUP) is that it is the fault of our measurement accuracy. A description that is often used is the fact that to observe the position of an electron, for example, one needs a probe, such as a photon, with a very short wavelength to get…
What is quantum tunneling Quantum tunneling is a phenomenon in quantum mechanics where particles exhibit the ability to pass through energy barriers that would be insurmountable in classical physics. It occurs when particles, such as electrons, exhibit wave-like behavior and are described by the principles of quantum mechanics. Quantum tunneling challenges our classical intuition and…
It is a bit pompous of me to think that I can actually tell you the most important thing you can learn from Physics Forums (PF). After all, each one of us here has different reasons for being on this forum, and so, we will have different things that we consider to be important to…
I am going to backtrack a little bit and talk about writing your Curriculum Vitae (CV) and what you should focus on in search of a job in physics. This includes looking for a Postdoctoral position, a research position, and possibly a faculty position at a university. I am going to base this…
If you intend to pursue an academic/research career, chances are, you will need postdoctoral experience. This is typically a 2 to 3-year appointment either at a university, national laboratories, or industrial laboratories such as Bell Lab. It is not uncommon for someone to do 2 postdoctoral positions before finding suitable employment. So this…
In the previous chapter, we have reached the point where you have finished with your thesis defense, and also thesis submission to the graduate school. You are all set to go into the nasty physics world and look for a job. If that is your case, then you are SCREWED! You do NOT…
At this point, you have completed writing your thesis, your adviser has approved of it, and you have distributed it to all the members of your thesis committee. It is now time for you to do your thesis defense. Officially, this is the final obstacle standing in your way between you and your…
At this stage, you have performed your doctoral research work, maybe even have published (or about to publish) a paper or two, and may have presented your work at a physics conference. It is time for you to think about finishing this part of your life. However, before you can do that, you…
I’ll try not to make a habit out of this, but I believe there’s something to add to this chapter of the series. In Part XIV, I mentioned the APS Meetings – March and April – which typically tend to be the largest yearly gathering of physicists. They both covered different areas of physics, i.e….
When I first wrote this part of the series, I wasn’t quite sure if I should include this. for most people submitting to most of the physics journals, this isn’t an issue. But considering the number of very bright students, we have on here, inevitably some of you might consider submitting a manuscript to…
I mentioned earlier that there are two ways for physicists to communicate their work. The first is via publications in peer-reviewed journals. I have covered this in the last chapter of this series. The second, which we will cover here, is through oral presentations at various scientific conferences. Each year, there are scientific…
At this stage, you are well into your Ph.D. research work, and depending on what area of physics you are in, you may already start producing new results. This next part of the series will cover an extremely important aspect of your graduate work that is typically not covered (sometimes not even required)…
Now, where were we? Oh yes! You have now started with your actual research work. You and your adviser have agreed on at least the general type of area you will be working in and you have started to do a lot of literature search of what is going on in that field,…
It has been a while since the last installment of this series, so let’s recap on where you are right now. You should already made a choice on the physics subject area that you want to work in, and you have picked an advisor who will be (i) supervising your Ph.D. research work…
In the previous part, I described the trials and tribulations of going through the qualifying exam that almost all graduate physics students have to go through. In this part, we will assume that you got through that very difficult part of your graduate program and now ready to do some serious, real physics…
You are now entering your first year of graduate school. In terms of the academic aspect, you will have a set of required courses that you must take. Typically, these courses would be advanced classical mechanics (at the level of Goldstein), advanced QM (at the level of Merzbacher and Sakurai), and advanced E&M (at…
I have decided to tackle this issue because it became a very common question in many physics forums. Can someone, without a degree in physics, get accepted and succeed in physics graduate school all the way to obtaining a Ph.D? Obviously, this question cannot be answered easily, because it depends on (i) your…
We are still discussing the final year of your undergraduate education. So far, we have covered what you need to consider if you want to go on to graduate school and prepare yourself as best as you can for that part of your journey. This is the “traditional” path that many physics students…
We are still stuck in the discussion of your fourth and final year of college. This time, I feel that a clear explanation of the US graduate school system is warranted, especially to others from the rest of the world who intend to continue their graduate education in the US. This is because…
We are still discussing the final year of your undergraduate program where you are in the midst of applying to graduate schools. In Part 5, I mentioned the word ”assistantship” several times, and it is important that you understand what this is, and why you should apply for it. So this part of the…
We have now reached the final year of your undergraduate program. By now, you would have gone through courses in the fundamental pillars of physics (Classical mechanics, Quantum mechanics, and E&M), and even courses in Thermodynamics/Statistical Physics. Academically, this is where you start taking more advanced courses, even some graduate-level courses. There are plenty…
So far, I have covered what I believe a student needs all the way to the end of the 2nd year of studies. In most schools in the US, an undergraduate must have a declared major by the end of the 2nd year (if not sooner). So by now, you should already be officially…
Part III: Mathematical Preparations In most universities in the US, a student must have a declared major by the end of his or her second year. So this is an important transition – making the commitment in a particular area of study. By now, if you have followed the first two chapters of this…
Part II: Surviving the First Year of College This part covers the survival tips of the first two undergraduate years. So now you’re in college, and you have every intention to be a physics major (actually, what I’m about to describe applies to anyone who is taking a physics class, not just for physics…
So You Want to Be a Physicist: A 22 Part Guide Introduction: The motivation for creating the series One of the most frequent questions we get in various physics forums and IRC physics channels (besides the annoying ”can anything travel faster than c?”) is the process and background of being a physics major. Often,…