Public vs. private

There’s nothing wrong with choosing to put a public school on a PhD application list if one has done his/her homework about subfields of interest beforehand. But the discrepancy between domestic and foreign students’ admissions standards is usually greater at a public school than at a private school. You should know by now that most schools will not accept students they can’t fund. If you earned a fellowship, or otherwise secured outside funding, yes, that might reduce the pressure on the department, but that doesn’t change the fact that even so, foreign admissions standards are higher even for those on outside funding. There is a reason for that: the tuition waivers that come attached to the funding (whether TA or RA).

Speaking of which, the cost of granting a tuition waiver to a student depends on the student’s state residency, because of the cost of the tuition being waived. How much do the cost of the tuition waivers explain the discrepancy in standards required from domestics vs. internationals is left to debate, but tuition waivers do play a role. And this would cause even out-of-state domestic students to be held to a higher standard than in-state students, but with no further disadvantage beyond that of state residency from that source. So here are two cases I’ve heard about at US public schools:

  1. University of California system. This is a system-wide issue, but UCs in general require out-of-state domestic PhD students to establish California residency within one year of the date of first enrollment, otherwise they will have to pay the difference between in-state and out-of-state themselves. Since establishing California residency is something an international student just cannot do on a F-1 visa, internationals cost more money on the long run. Also UC Santa Barbara is a campus known to have reduced the quotas on international students, to the point that the number of international admits can be counted on one hand for the 2014 cycle, and all other UC campuses are likely to follow suit in the near future, invoking that much of the research conducted at UCs is state-funded (NSF, state appropriations, etc.) and that they wish to keep the funds in the country.
  2. University of North Carolina system. By state law, all public schools in the state of North Carolina (other than UNC School of the Arts, NC A&T engineering and MD/PhD programs, the latter because of NIH regulations) must enroll at most 18% of out-of-state students, internationals included. EDIT: UNC campuses enforce the 18% cap at the campus-wide level, leaving some leeway to enroll more out-of-state PhD students if the need arose.

On the other hand, private schools usually charge the same tuition regardless of the student’s origin, in which case the discrepancy is not explained by the cost of funding a student, but simply by the sheer talent to be found in the applicant pool.

Online resources beware!

Undoubtedly some people that want to earn a PhD have some use for some of the following resources:

These websites have their uses, but many users of these websites are quite neurotic, and their users tend to be among the better candidates. That is not to say that lesser applicants can’t find any use for them, even if they had to live with non-elite programs; just that most people willing to post their profiles are much better than average.

So please take in account that the profiles posted are skewed towards the upper end, and pay attention to any observation bias caused by these tendencies if you elect to use these resources.

Physics GRE: The content

Long ago, I covered the tips to study for the physics GRE, but leaving out the actual content. You shouldn’t spend too much time ‘studying’ for the GRE in the conventional sense of opening up books and reading. However, it does help to have a map of what you’ll be studying for. (If there are any Quebecer undergraduates reading this out there, I can confidently say that you can take the test in April of your second undergraduate year and still score quite high, provided the roadmap I laid out is in use) Your best bet is to look at the general breakdown of questions, available in the practice booklet and on ETS’s informational webpage. I encourage you to actually read the detailed breakdown of each topic and make sure you are familiar with them. Below are my rough interpretations of the level at which the Physics GRE exam will require facility in each general topic. As a convenient scale I’ll use some textbooks, most of which I actually used.

  1. Classical mechanics (20%) Most questions are CEGEP-level (i.e. introductory undergraduate physics) so I would recommend using a textbook of that level (e.g. Benson, Halliday and Resnick) although questions about Lagrangian and Hamiltonian mechanics, as well as central-potential questions, are at the level of the Taylor.
  2. Electromagnetism (18%) Even though the calculations are, again, at the level of Benson (or Halliday and Resnick), for the conceptual content, other than circuits, Griffiths’ Introduction to Electrodynamics will suffice. You are expected to know qualitative relations for the more advanced content, but, for the material pertaining to AC/DC circuit, you can always refer to the material in an undergraduate lab course. Even introductory electronics textbooks may seem like overkill here.
  3. Optics and wave phenomena (9%) Once again, most questions can be found in an introductory-level textbook.
  4. Thermodynamics and statistical mechanics (10%) You need not have taken a complete course in thermodynamics or statistical physics, although some partition functions and basic stat mech can show up. Schroeder is definite overkill.
  5. Quantum mechanics (12%) Here Griffiths’ Introduction to Quantum Mechanics covers your bases and then some. For anyone that took courses at that level or above, the questions are quite easy.
  6. Atomic physics (10%) What atomic physics is covered in Griffiths’ QM textbook as applications of QM will have covered everything you need.
  7. Special relativity (6%) I’d say that Benson’s chapter 8 in tome 3 is sufficient; Griffiths EM chapter 12 is overkill. No 4-vectors.
  8. Lab methods (6%) No single textbook will be of any help to you here but the material is covered in an undergraduate-level lab course.
  9. Specialized topics (9%) Too often students will make the mistake to overfocus on that component of the test. This segment will primarily cover condensed matter, astrophysics, nuclear and particle physics; I neglected condensed matter questions myself because I didn’t want to do condensed matter in graduate school.

Bottom line: if you’re an US resident, you can get a score high enough to get into an Ivy League physics PhD program (grades and research experience pending) with only the introductory textbooks to work with. If you actually did that, however, you’d be most likely be attending a “lesser Ivy”, should you get an Ivy League acceptance at all; in a physics context, this means UPenn, Brown or Dartmouth, in descending order of difficulty. In fact, to meet UPenn’s latest average (70th percentile), you need to answer ~60% of the questions right. Lesser programs can do with a lower amount of correct answers. Vanderbilt and Dartmouth, two programs that are similar in many respects (housed in highly prestigious universities, not-that-well-regarded, a collection of physical disciplines with similar representation), can make do with a 50th percentile. This meant answering 44 questions back on Form 0877, 38 questions back on Form 0177…

A warning to high schoolers

Although most posts I previously wrote were related to the application process for graduate school, this time around I am talking about how to shop for an undergraduate education with a major in mind, It’s perfectly understandable that one might want to shop a college with a major in mind, provided one’s credentials and budget are accounted for. And one may very well be tempted to shop for an undergraduate education with a graduate guide. Again, I can understand why one would even do so, but, in my opinion, graduate guides are good gauges for only one aspect of undergraduate education: research internships.

There are schools who, without question, do a great job of educating both undergraduates and graduate students in a given field (my undergrad is one as far as physics is concerned), and others who do neither. But, quite often, there is a tradeoff being made: often, at research-intensive departments, the professors will be more preoccupied by research, they won’t put much thought into their teaching, even though many faculty teaching contracts have some stipulation that, in non-sabbatical years, they have to teach undergraduates. And, especially in the natural sciences and in engineering, undergraduate teaching labs may not stack up against research labs.

One could say that such a discrepancy between graduate and undergraduate isn’t usually so great because the professors know their subject matter (and said professors are the same for everyone), because the library collections are accessible to every student. Humanities and social sciences are usually not fields where discrepancies between undergraduate and graduate education are considered as either common or large.

So, in essence, if it’s possible for you to check whether undergraduates seem to get a great education or not, consider doing it prior to application; if a college requires a “Why X” essay, then you may use the contents of your communications with students.

Academia: the types of environments

Many PhD hopefuls want to earn a PhD so that they can, long-term, teach in a university. That’s perfectly understandable, but I have heard so many PhD hopefuls/students that aspire to work in academia that they preferred to teach in departments with graduate programs. I am going to go against the current and say that I would rather teach at a physics department without a graduate program. And many undergraduates who eye graduate school actually study at departments offering graduate degrees as well. Let’s say that I never heard about liberal arts colleges until late in undergrad (Middlebury was the first one I ever heard about, and then Amherst, Williams, Swarthmore) or full-fledged universities (the definition of a university I personally use is: an institution of higher education offering at least one graduate program, conferring at least one advanced degree yearly) whose physics (and sometimes astronomy as well) department does not offer a graduate degree.

I learned about the latter during my advanced statistical mechanics class. The professor didn’t stop lecturing about the statistical mechanics phenomena observed in white dwarves, and white dwarves in general; I can’t blame him because he is one of the leading white dwarf scholars in the world. He mentioned the Villanova White Dwarf Catalog, named after an astronomy department that did not offer a graduate degree. Yet Villanova is one of the foremost schools in the US for white dwarf research, second only to the University of Texas at Austin. But how most departments that still somehow maintain some research activity manage to do so despite the lack of graduate students are, in fact, doing it with a copious amount of summer internships (by the standards of such departments, budget permitting) or with senior theses. In fact, a combination of both is likely in use at Villanova (not in particular but I suspect Villanova is representative of what happens at that sort of schools).


Schools with graduate programs:


  • You can perform research year-round on projects whose scale and scope is larger than at non-graduate departments
  • You can train graduate students
  • Your teaching load is lighter and you have the opportunity to teach advanced coursework


  • You are expected to publish and to win research grants
  • The responsibilities of labs and graduate students are actually quite heavy and you have to deal with them year-round
  • The temptation is very great to favor graduate students over undergraduates

Schools without graduate programs:


  • You are not expected to pursue grants and publications as intensely
  • You don’t have to deal with the stress of dealing with research students year-round (or at least it takes less room, and it goes without saying that lab responsibilities go hand-in-hand)
  • You have more freedom to choose research topics provided the research can be conducted without the need for large budgets (especially appealing for theorists)


  • Your teaching load is heavier
  • You may not be able to contribute to research as much
  • You may not be able to teach advanced coursework as you would have liked to

Nevertheless, regardless of whether one teaches at a department with or without graduate programs, a faculty job at the university level is highly stressful.


Internal competition: strategic planning, negotiations and publications

Now that I have removed Harvard and Princeton, having just realized how unrealistic they were in my context, while I still held on to UPenn, I was still freaking out, searching frantically for both a replacement to Harvard and Princeton as well as a way to strike a deal to ensure that this particular person will not apply to UPenn, despite the fact that the only ones who know about UPenn in my home department collaborate with others in soft condensed matter projects (experimental or theoretical). Unfortunately, perhaps I was a little naïve to think that negotiations alone would resolve the issue, knowing that neither side can resort to sabotage.

To ensure the negotiations wouldn’t fall apart, I had to double-check whether UPenn offered what physics she wanted (or whether soft condensed matter was acceptable to her eyes) but also what alternatives I could put on the table. Since I was quite confident that she could score high enough on the physics GRE for it not to be an issue, I had no qualms about suggesting Cornell and Stanford, in that order, given her desires as a condensed matter experimentalist. But someone pointed out that perhaps I am a little too hung up on the “publications” part of her dossier, and that the realities of our respective subfields are quite different.

To wit: experimental condensed matter is easier to get involved in early in an undergraduate career (some even say it’s significantly easier) compared to theoretical particle cosmology, due to the  more-or-less-vast discrepancy in background requirements as far as having the capability of contributing is concerned. Three summer internships, two publications. I know not in what capacity she took part in the research leading up to these two publications, but one thing is for certain: she isn’t an endorser (and, in condensed matter, endorsers are listed after the least contributor, in order of the importance of their material contribution, if they are individuals rather than organizations) even though she didn’t necessarily understand the whole shebang. In theoretical particle cosmology, one can’t really get started until quite late in undergrad: QFT, general relativity, topology are rather advanced tools. And authors are listed in alphabetical order, an artifact left behind by particle experimentalists and the sheer scale of the collaborations required for their experiments. Even so, IMO two publications done as an undergrad in experimental condensed matter are worth more than one theoretical particle cosmology publication (and that’s if we can get it done by the application deadlines) as a masters student.

Even though many Cornell and Stanford (as well as Harvard, Princeton, UPenn and so on, so forth, although maybe not at Vanderbilt or Dartmouth) PhD matriculants have publications, not so many of them did so as first author. However, this begs the question: to what extent do admissions committee take in account the circumstances (subfield, order of authorship in a publication, # of citations, etc.) under which the publications were written?

Addendum: I got the confirmation that she isn’t even considering UPenn at all, so all I can say is that I was in a sorry state for three days.

Internal competition

Yesterday, on my way to the laboratory, I met with an undergraduate on a condensed matter experimental internship. Little did I know that, while she wanted to conduct research in photovoltaics or organic semiconductors, which are, in fact, condensed matter topics, her file was a lot better than mine. And I then gave her advice pertaining to the GRE if she felt like she would be better served at an institution that requires it. Because, notwithstanding the GRE (both the general and subject tests) and that it is generally easier to publish as an undergraduate in experimental condensed matter than in particle cosmology, my own file is, by my own admission, below hers. For this reason, I feel targeted and I feel the need to commence negotiations with her so as to minimize overlap at the top of our common application lists. I have yet to receive a response on her part, though.

My advice: If you aim for highly-ranked programs, do not apply without first inquiring about the credentials of your classmates that intend to do the same, because you should be wary about internal competition. Many highly-ranked universities will not admit more than one student from an institution unless there is a glut of highly-qualified students applying from that place. If there is a large difference between you and another student and that you happen to be the lesser student of the bunch, consider dropping a school from your list if it is a reach to you. I know it is heart-breaking but sometimes maximizing the success of the class means making individual sacrifices.

PhD application timeline

Unlike conventional wisdom where the timeline for applications begins in summer of your junior year in undergrad (depending on the country, this can be end of the second or third year) or if, for some reason, you put off the PhD application process until well into a masters program, the first year in masters, I recommend beginning the process during the winter. This is a best-case scenario which leaves time to craft a great application and resolve unforeseen issues (lost transcript, a delinquent recommender). Of course, you have to tweak the later part of this schedule to fit the schools’ deadlines. If you wish to earn a PhD from a school that does not require neither the TOEFL/IELTS nor the GRE (general and/or advanced), you may skip the steps pertaining to these tests.

  • February: Take the TOEFL/IELTS (if applicable) and/or the general GRE (preferably the TOEFL/IELTS prior to the general GRE since verbal and writing preparation for the GRE overlaps with TOEFL/IELTS practice if you need take both)
  • April: Take the subject GRE (if applicable; test scores from the April administration are released ~30 days after the administration)
  • May: Begin researching potential programs. Your scores will help you determine whether these programs are worth applying or not. At the same time, begin writing your personal statement.
  • June: If, after checking against the deadlines of your potential schools, you realize that the transcripts with fall grades won’t arrive in time, and that they won’t accept transcripts in your native language, then begin looking for certified translations as soon as the originals are released. Consider contacting professors at your current institution (or former if you’re out of school); they may help you recommend some programs and even make some connections.
  • July: Request information from institutions that interest you. If you’re not happy with your GRE scores (general and/or subject), sign up to take the relevant tests again.
  • August: Finalize your list of prospective programs, and pick a professor or two from each whose research interests mirror your own. Familiarize yourself with their work. Keep polishing your personal statement in accordance with your pick of professors. Make contact with students and professors at your prospective schools (especially the ones closest to your research interests)
  • September: Contact your recommenders; include supplemental materials (unofficial transcript, personal statement, resume) so that they can use them as reference. Have someone in your field review your personal statement.
  • October: Request official transcripts from your institution and send your GRE scores directly to schools. Arrange a campus visit if you can.
  • November: Complete and submit all applications, keeping a copy of all sections for your records. Verify that your recommendations are sent. 
  • December: Focus on financial aid – look into private grants and fellowships (and loans as a last resort).
  • February and March: Try to relax while you wait it out. This is the more relaxing time you will have in years, so enjoy it while it lasts.
  • April: If you’re accepted to multiple schools, this is going to be a stressful period because the implications reach far and wide into the future.

Some GRE-taking strategies

Perhaps I have written too many posts about the GRE and different aspects of preparing for the test. I kept talking about preparation all this time, but I gave little to no indication about test-taking strategies. Now, if you followed either the roadmap or the list of general GRE study plans, you should be familiar with the content and the format. But some of these tips are subject test-specific and others are applicable both to the general and subject GREs. Let’s begin with the tips applicable to both the general and subject GREs.


  1. Answer the questions you’re confident about first. Remember, the GRE is a test where time management is crucial. If you answer the questions you’re confident about first, you would then save precious time that could be better spent on trying to solve the more difficult problems. Which leads to the next tip…
  2. Pace yourself. That doesn’t mean that you should spend as close to 2 minutes as possible on each math question, or close to 1 minute as possible on each verbal question. 2 minutes seems a little long to answer a math question but, when you start doing the calculations, you could realize that it is at a premium.
  3. Use the scratch paper. You will not be allowed to bring paper to the testing center with you, but you will be provided with scratch paper (on subject tests, the reverse of each page with the items contains scratch space). Use it to help solve math problems, outline your essay for the writing portion or write down formulas or vocabulary words you’ve memorized before the test.
  4. Use the elimination techniques at your disposal before guessing. If you can eliminate even one wrong answer (e.g. through dimensional analysis, limiting behaviors, unit consistency on the subject GRE, an answer choice whose meaning is opposite to another answer on the verbal part of the general GRE) you’ll be in a much better position to guess if it came to that. What form the penalties from guessing incorrectly on the GRE take depends on whether you are talking about the general or the subject GRE. On the general GRE, you might not be penalized on your raw score for bad answers, but the raw score of the first section determines the difficulty of the second one.
  5. Don’t second-guess yourself too often. Statistics suggest that your first answer choice is usually correct as long as you’ve prepared well for the exam and have a solid knowledge base. Do not go back through the test and change your answers on the paper exam unless you’ve discovered information that leads you to a new conclusion or you realize that you didn’t give yourself enough time to thoughtfully consider the question on the first try.


You may realize that there are tips that apply only to one section or one test. Here are the personal tips I used…


  1. (Verbal section), look at the answers before looking at the question. Instead of plunging ahead into the text, read what you need to be looking out for. You’ll save time and score more points by reading the answer choices before you read the text.
  2. (Analytical writing section), outline. It may seem like old hat, but you can’t disregard the GRE writing section. Before you start writing, make sure you take five minutes to outline what you’re going to say first. Your organization and thought process will be much higher if you do.
  3. (Subject tests), do not wait until the end to mark the answers on the sheet. It could cost you precious time if you did so, precious time that you could use for reviewing troublesome questions.


You may have also realized that general GRE tests and subject tests are quite different, not only in content but also in scoring. Whereas there are questions on the general GRE where multiple answers are acceptable, or even required, on the subject GRE multiple answers are not scored. Subject tests penalize you for any wrong answer to the tune of 1/4 of a raw point apiece. Hence the need to be able to eliminate at least one incorrect answer before guessing on a subject test which, scaled, is, in theory, scored from 200 to 990. In practice, on some tests, the actual ceiling is lower than 990, and the actual floor is higher than 200; for this reason, subject test scores are often reported as percentiles. And the general GRE is scored from 130-170 for verbal and quantitative, and 0-6 for writing. Which leads me to what constitutes a good score. Of course, this is very program-dependent, so what is good for one program is not necessarily good for another; however, not many programs will post the average scores of admitted students.

For informational purposes, here are the averages for UPenn’s physics PhD program (my first choice, now that Harvard and Princeton are removed from my list, replaced by Brown, itself replaced by UChicago and UNC-Chapel Hill): V626/162 (86th percentile; however, non-native English speakers are removed from the equation), Q780/163 (88th percentile) with no AW average posted.

Letters of recommendation issues

Disclaimer: from now on, the feminine form will designate both genders when it is necessary not to discriminate for a gender when writing in the third person.

Every PhD program will ask you for three (or less commonly, two) letters of recommendation. These weigh heavily to the eyes of the committee responsible for the admissions process so choose who will write them wisely. Whenever the option is given, please waive the right to see the letters; if you do not, it will be taken less seriously. And, unlike MBA admissions, where it is quite common for recommenders to ask you to write a letter of recommendation so that they can transcribe and sign it afterward (a few will do the appropriate modifications in due course, e.g. if the recs are to be sent on official business letterhead), here it is not recommended to write the letter yourself so that the referee can transcribe and sign.

Some people might say that the referees are mostly “go big or go home” in that respect and, therefore, letters of recommendation do not mean as much as they used to. However, even if you chose someone who knew you well, and not simply because you earned a high grade in their course (especially if it’s a challenging course), or collaborated in research with you for a short period of time, if they can only write a neutral letter at best, you’d be better off asking another person that knew you well in some capacity (preferably in a research capacity).

If you did enough work with someone to earn a co-authorship with her, then by all means ask that person first. If someone is well-known in a field, it will carry significant weight but the recommender’s fame in a field won’t necessarily outweigh a strong research-driven letter written by a lesser-known scholar if the famous referee wrote his/her letter for coursework reasons. And a research-driven letter will generally be stronger if you published with a given referee than if you didn’t publish. So make sure the referees will be specific enough in their reasons for recommending you because your recs will be a lot better that way. Because, alas, some professors will be rather generic in their writing and write nearly identical comments for every student they vouch for.

If you exhaust your research-driven letters before you go to the count of three, don’t fret! But you still have to choose a referee according to how advanced the course you took with her was, as well as the grade in that aforementionned course. Among coursework-driven letters, the better letters will usually come from a professor that taught you an advanced course in which you earned a high grade.