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 is wrong because it has been superseded by Special Relativity (SR) and General Relativity (GR), and/or Quantum Mechanics (QM).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 tackled 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…
Fake News, Data, and the Need to Check Sources During and even after the recent US election campaign, numerous reports of fake or misleading news were circulated: outright fabrications, inaccurate summaries, and incomplete reporting designed to push one point of view or another. Outright fabricated stories are often exposed eventually, but subtler misreports — especially…
QM’s formalism Strangely enough, quantum mechanics (QM)’s formalism isn’t any more difficult than other areas of physics. The mathematics of the “standard” QM isn’t any worse than, for example, electromagnetism. Yet to many people—especially non-physicists—QM presents a daunting effort to understand. Why QM often feels difficult I strongly believe this difficulty comes down to how…
I posted this elsewhere (on my 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 this…
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, the energy gain after going through the field is always eV, no matter how far away it has to move. For…
Have Scientists Seen an Electron? Why Seeing Isn’t Enough This article is not about literally seeing a single electron with your eye; it addresses the broader—and common—belief that direct visual perception is the only valid form of evidence. I will show that the human eye, as a light detector, is NOT a reliable detector in…
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, several 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 other words,…
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…
Can You Quantum Tunnel Through a Wall? The short and sweet answer if a tennis ball, a bowling ball, or any other kind of ordinary macroscopic object can tunnel through a wall is NO. You can’t quantum tunnel through a wall. We periodically get questions on PF about people wanting to know if a tennis…
It is a bit pompous of me to think that I can 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 us….
Curriculum Vitae (CV): What to include 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 base…
Postdoctoral Positions What is a postdoc? If you intend to pursue an academic or research career, you will very likely need postdoctoral experience. A postdoctoral appointment is typically a 2- to 3-year position at a university, national laboratory, or an industrial lab (for example, Bell Labs). It is common for people to take two postdoctoral…
Start your job search well before graduation In the previous chapter you finished your thesis defense and submitted your thesis to the graduate school. Although that feels like the end, your job search should have begun earlier—about one year before you plan to graduate. If you wait until after your defense to start looking, you’re…
Overview: The Thesis Defense At this point you have completed writing your thesis, your adviser has approved it, and you have distributed it to all members of your thesis committee. It is now time for your thesis defense — the final formal hurdle between you and the Ph.D. degree. Adequate preparation is essential. What is…
Introduction At this stage you have performed your doctoral research, maybe published (or are about to publish) a paper or two, and may have presented your work at a physics conference. It’s time to finish this part of your life. Before you can graduate, however, you must complete two final obstacles: writing your thesis (dissertation)…
Overview of the APS March and April Meetings 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 are typically the largest yearly gatherings of physicists. They cover…
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…
Why attend physics conferences? I mentioned earlier that physicists communicate their work in two main ways: publications in peer-reviewed journals (covered in the previous chapter) and oral presentations at scientific conferences. Conferences, workshops and meetings occur worldwide for many subfields of physics. Two of the largest annual events are the American Physical Society (APS) March…
Publishing your Ph.D. research in physics journals At this stage you are well into your Ph.D. research and may already be producing new results. This chapter covers an important but often under-taught part of graduate work: publicizing your research. Graduate curricula rarely include systematic instruction on how to publish, yet publishing is central to a…
Starting Your Research and Keeping Good Records Now, where were we? Oh yes — you have started your actual research work. You and your adviser have agreed on at least the general area you will be working in, and you have begun substantial literature searches: what is known, what is unknown, and what are the…
Initiating Research Work It has been a while since the last installment of this series, so let’s recap where you are right now. You should have already chosen the physics subject area you want to work in, and you have picked an advisor who will be (i) supervising your Ph.D. research work and (ii) the…
Choosing a Research Area and an Advisor In the previous part, I described the trials and tribulations of going through the qualifying exam that almost all graduate physics students face. In this part, we will assume you passed that very difficult milestone and are now ready to do some serious, real physics work: choosing a…
Starting Graduate School: Coursework and Campus Life You are now entering your first year of graduate school. Academically, you will typically take a set of required courses that form the core preparation for all physics graduate students. These commonly include advanced classical mechanics (Goldstein level), advanced quantum mechanics (Merzbacher / Sakurai level), and advanced electrodynamics…
Can you enter physics graduate school without a physics degree? I decided to write about this because it is a very common question on many physics forums: can someone without a physics degree be accepted into and succeed in a physics Ph.D. program? The short answer is: it depends. Two main factors matter: (i) your…
Nontraditional career paths for physics graduates 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 how to best prepare for that part of your journey. That is the traditional path many physics students…
Understanding the US Graduate School System We are still in the discussion of your fourth and final year of college. This time I’ll explain the US graduate school system, especially for readers from other countries who plan to continue their graduate education in the United States. From conversations I’ve had, there is often confusion about…
Assistantships in US Physics Graduate Programs We are still discussing the final year of your undergraduate program, when you are applying to graduate schools. In Part V I mentioned the word “assistantship” several times; you must understand what it means and why you should apply for one. This installment focuses solely on assistantships as they…
Senior Year — Preparing for Graduate School You have now reached your final undergraduate year. By this point you have completed core courses in the pillars of physics — classical mechanics, quantum mechanics, and electromagnetism — and most students will also have taken thermodynamics and statistical physics. Academically this is the time to begin taking…
Becoming a Physics Major (End of Year 2) So far, I have covered what a student needs through the end of the second year of study. In most U.S. schools, undergraduates must declare a major by the end of the second year (often sooner). By this point you should already be an official physics major…
Part III: Mathematical Preparations In most universities in the U.S., students must declare a major by the end of their second year. That decision is an important transition: committing to a particular area of study. If you followed the first two chapters of this series, you should already be aware of the general background needed…
Part II: Surviving the First Year of College This part covers survival tips for the first two undergraduate years. You’re now in college and intend to be a physics major — though much of the advice here applies to anyone taking physics classes, not just physics majors. Advising and the calculus sequence In most U.S….
So You Want to Be a Physicist: A 22-Part Guide Introduction: The motivation for creating the series Why this 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: what is the process and background of being a…