@SirCumference that depends on where you are in a research cycle. early on, you'd sit down and read papers, obsess over their details, and talk to colleagues. After that, you'd obsess over equations; trying to work them out on paper and rearrange them into interesting forms. Next, a day might involve writing code all day or running computer simulations and modifying initial conditions
@Jim My grant wants me to have result in a few weeks. Not sure how they expect me to do that in three months. Lit review took two months.
Anonymous
@Jim I'd like to know what advice you have for undergraduate electronics engineering student (i.e. me) who wishes to pursue a career in physics and is more inclined towards application but enjoys theoretical physics too. What are some of the undergraduate projects that I should take part in? And what courses apart from my engineering courses should I take to enable me for higher studies in physics?
Anonymous
Also, would it be helpful to take in initiative in writing a research paper on a topic that interests me? Or would it be better to just take part in summer physics workshops/projects in nearby universities?
@SirCumference That's an interesting question. It means a lot of reading recently publishings, going to conferences and colloquia, talking to peers. Basically you try to learn as much about new research as you can until you go "I wonder about this. What happens if we extend that or if this is the case? Can we do this?"
@Blue as for the courses, talk to the undergrad physics advisor. Every school is different. I talked to mine in advance and she old me what courses would make it more likely to get me into grad school in physics. I can tell you to take quantum mechanics, EM, math, SR, math, statistical physics, and math
If you like application more, do some experimental physcis
@Blue don't just write your own paper; at your stage, it's best to do a project for a prof and try to get attached to their paper. Someone with a reputation is the best for working you into the field
Anonymous
@Jim Who is an "undergrad physics advisor" ? Any physics prof from my university who is willing to help me out?
@Jim Interesting. Though considering how many cosmologists there are in the world, isn't it likely that someone has inevitably answered your question already?
@Blue usually, there is a prof designated as the advisor for students. I can speak for all schools, but when in doubt, ask the head of the department/faculty.
@0celoñe7 I was looking at Witcher 2. Could jump ahead a bit I guess
Anonymous
@Jim Makes sense. I'll try talking to someone from the physics department. Thanks for your advice. :)
@Blue Are you sure it was due to your family who forced you not to study physics, or rather because you, yourself, also found their concerns (about your possible future career if you study physics) reasonable?
@SirCumference I'm asking this because it happens to a lot of people in countries like India or Iran. And I think the society should be blamed here, not one's parents.
@SirCumference no, this is why you look at recent publications. They are answering a question for the first time. If you have a question from that, then it is likely unanswered. However, it is always best to research your question to ensure it's unanswered. And it is definitely a thing where you'll spend time researching it only to have someone else publish first. That's why make scientists race to put out a first publication on a topic they start.
It lets them establish it as theirs and keep working at their own pace
> I wonder about this. What happens if we extend that or if this is the case? Can we do this?"
My issue is that I already have loads of questions like these before I even crawl through 1/1000 of the literature, which means I bump into the wall alot when I realised they are already answered
@SirCumference it's the opposite more often. As an engineer, I was trained to write ideas in a way that they'd be most easily understood by even a novice to the field. Unfortunately, that tends to make my work seem less significant than it is. Especially when other scientists have a practice of obfuscating their work. The harder to understand, the more likely reviewers think it's good and push it through.
Anonymous
I did have an option of Physics + Computer Science dual major at a good university called BITs Pilani but since it was a 5 years course instead rather than the conventional 4 year BTech my parents didn't allow me. They unfortunately want me to become "employable" as soon as possible. If given a choice I would have happily gone for the Physics+Computer Science dual major at BITs Pilani.
Anonymous
@Mostafa Both actually. First of all an undergraduate physics degree is not valued at all in India. You need to have atleast a PhD in Physics to be taken for a job or a professor at any university. While an undergraduate degree in Electronics gives you much greater job security and also a chance to change field to physics. I intend not to pursue my higher studies in India anymore as physics research is not encouraged here as such.
@SirCumference I agree. I hate it. But when they want something published that isn't worth it, they make it seem more important by complicating it. My supervisor and I once both wrote separately about our joint work. Both papers described the same thing, but mine was simplistic and straightforward. His was complex and messy. His seemed way more important even to me, and I understood it
But this a reality that many of the students who really love to study physics or math are forced (the question is by who?) to study engineering (or even medicine).
@SirCumference absolutely. It is a time to do research, make a name for yourself, and show what you're capable of. It sets you apart from the rest for when you apply to be a professor
Anonymous
1:21 PM
@Mostafa Same here. And I guess it is same for all developing countries which need more engineers than physicists. :P
@Jim That's good to know. Also, have you ever disagreed with someone as to who should be the lead author of a paper? How would you go about solving that?
@SirCumference not for the lead. Usually it's fairly obvious. And if there's a person deserving of the lead authorship, they can usually have enough power to wield to make sure they get it. I did disagree once about who should get second author.
@Jim Alright. One more question before I have to go: As a professor, how do you make your teaching as intuitive as possible, if you have to cram a lot of information into a single semester?
I had done half of the work and writing for a paper. My supervisor did the harder half. Obviously he got first. I felt I should get second, but he gave it to a colleague of his from England that I'd never heard of before. I asked about it and he said the guy gave novel ideas for the direction. I was unhappy, but couldn't do much to change it. I was a masters student
@Jim Are you working at the University of Toronto? one of my undergraduate friends (actually one of the very close friends!) started his PhD in EE, information theory, last year (2016) in Frank Kschischang's group :)
@Blue Canada for a few reasons. First, it's more familiar to me and closer to family. Second, I'm not a fan of the current politics or social structure of the US (no offense, but it's different than what I'm used to). And third (most important), they require to to complete the GRE exams to do grad school there. With my disability, time-based tests like that are extremely difficult to complete. It's an unfair disadvantage when I have to constantly reread questions in the same amount of time
@0celoñe7 The Dandelion sequence drags on even longer the second time ;P It's interesting to see which things certain actions change and which they don't, though.
@ACuriousMind I don't like how the Baron story was "resolved" in my playthrough.
Anonymous
@Jim From here it seems they accept TOEFL and GRE scores in Canada also. So that makes US and Canada similar for me. :P I'd probably apply to both the countries
anyway, this will have to be the end of the AMA with Jim (long may He reign). I have to get to my job. But I'm still around if you don't mind being answered a bit late
Anonymous
1:38 PM
But, yeah. One good thing is that the cost of education is lower in Canada. :)
@0celoñe7 I think Ciri's fate is less about being "nice" to her and more about trusting her to do the right thing vs. trying to tell her what's best like everyone else does. It's also not really about taking the reasonable course of action (cf. trashing Avallach's lab).
@0celoñe7 I'm not sure I really like any of the resolutions
Probably that's kinda the point - the situation is beyond getting truly fixed.
@Jim Well thanks for showing people with disabiltiies can succeed.
I consider myself a success in that way, and it grinds me down to see both people thinking it can't be done, and people with disabilties helping to enforce that view by either being lazy and claiming it can't, or using it as an excuse.
> It cannot be made precise in the context of QFT because the quantum field is operator-valued and has no definite values, so it is wholly unclear what rigorous sense could be given to it being "excited".
@0celoñe7 Not so sure - choices like whether to trash the lab or to accompany Ciri to the meeting with the sorceresses don't strike me as nice vs. not nice
@0celoñe7 When you are in Avallach's lab Ciri get's angry and starts smashing something and Geralt can either calm her down or join in, iirc. And the meeting is in Dandelion's tavern where you either go in with her or listen at the door with Yen
@0celoñe7 Well, I'll grant that she's not entirely rational about that - but I don't think that's a flaw in the game, only a flaw in her character (though I find it hard to fault her for it)
It's easy to forget that this isn't a blank slate character - Geralt comes already with a lot of baggage and a certain...inability for diplomacy before the player starts projecting on him
Also, his emotions are subdued and/or altered due to being a witcher, so he lacks the kind of empathy the fully human player would have used to choose a better response than the choices given.
(which is why computer RPGs will never be a full substitute for playing RPGs at a table with other people)
@0celoñe7 Morrowind...doesn't have a lot of choices in that sense. You decide which factions to join (some are exclusive), but most of the quest lines are fairly linear
@0celoñe7 Mass Effect had a far bigger problem with "Renegade" often just equating to being pointlessly rude or cruel to people, imo
@Slereah Well...I'd rather say it's bunch of linear narratives that you can also completely ignore and just go explore random places :D
That's the thing that really hasn't changed in the later iterations. What Oblivion and Skyrim lack is the delightful strangeness of Morrowind's setting.
Right in that case, I don't see the problem of having a tensor field to have a localised excitation by being somehow bounded, compact, or have finite support
Unless, being lorentz invariant is not a sufficient condition for operator valued fields to be tensors...
@ACuriousMind I am thinking about this part of your answer to user400188. Sure, the observables don't have definite values until they are measured, but the underlying mathematical construct (wavefunctions in QM and operator valued fields in QFT) should be as a whole a well defined object. Since it is covariant, do operator valued fields form a tensor field and hence we can define its local exictation by considering that the operator to obey something like compact, bound or finite support notions?
> It cannot be made precise in the context of QFT because the quantum field is operator-valued and has no definite values, so it is wholly unclear what rigorous sense could be given to it being "excited".
@0celoñe7 Ah, a "covariant theory" is one whose action is invariant under coordinate changes. It's kind of a silly thing to say about a field theory because almost all field theories are like that, but then again many people don't seem to understand that coordinate invariance is not really what makes GR special, so I wouldn't worry to much about that phrase
@0celoñe7 You've got to download matchmaking game server program and block korea ip so you won't face them anymore whenever matchmaking of Steam tries to join you to the game.
@Secret Your point being? Yes, you can say that the field has compact support. But the field is operator-valued and this operator-valued distribution does not encode the quantum state.
@ACuriousMind Just as a localised excitation of a classical field can be defined as the field having nonzero values in some finite "small enough" region, since operator valued fields are tensors, we can perhaps make sense of a localised excitation of the operator valued field by requiring all operators to have finite support (or other notions such that the operators don't do unbounded things)?
@Secret You can do that. Then you have defined a notion of "excitation of a quantum field" that exactly no-one else uses. What are you gonna do with it?
@Secret the quantum field is a mathematical object not a physical one. The quantum field presumably describes some physical object, and you can presumably have excitations of whatever the quantum field is describing ...
@Secret You can have operator-valued tensor fields. What's your point? Why are we even talking about covariance? Once again, I have no actual idea what you are talking about, or why.
@JohnRennie for what it's worth, I am actually paying penance over it, in the form of having to defend the spirit of that comment over and over and over again
I suspect Johnrennie has said something important here. I think I might have a misconception that the quantum field encodes all possible information of all possible ways a given quantum state will be transformed, analogous to how wavefunction encodes all information about a quantum state
@Secret the quantum field is a mathematical object not a physical one. The quantum field presumably describes some physical object, and you can presumably have excitations of whatever the quantum field is describing ...
@0celoñe7 If I fire two rocket motors in different directions the vector sum of their thrusts give the total thrust I experience. Isn't that physically meaningful?
and thus me thinking (perhaps wrongly) that an excitation of the quantum field in terms of imposing some condition on all its operators will thus describe all the possible excitations that any arbitrary quantum state will experience under said field.
so for the example of the momentum operator, although it does not encodes any specific quanutm state, any quantum state, when fed to it, will produce the momentum eigenvalue
@0celoñe7 I was just thinking aloud. There was a question (now deleted) about what you'd get if you added a vector and pseudovector, and I was wondering if the question even made sense.
@JohnRennie Well, it won't be meaningful in that way since the result of adding a vector and a pseudovector doesn't transform in a good way under reflection. Geometrically, what you've done is adding a representation of a direction and a representation of a (hyper)plane, which yields a representation of...nothing in particular.
@JohnRennie Well, when people are taking huge open problems and decreeing them to be unimportant edge cases, they deserve to have that made explicitly clear to them
@ACuriousMind I know if it is the momentum eigenstate, it will give you the momentum of the state as its eigenvalue, but if the state is not an eigenstate of the momentum operator, you get some other state, but isn't the momentum operator always tell you something about the distribution of momenta of the quanutm state?
@EmilioPisanty no-one is dismissing the problem of baryogenesis. The point of my answer is that the physics responsible acted at energies far above any lab experiment on a beaker of anti-water.
My point being that whatever caused the CP violation that produced a matter excess isn't going to make a glass of anti-water look different to a glass of water.
@ACuriousMind Hmm. Do you think "bounded in $C^\infty$" means "all partial derivatives are uniformly bounded by the same constant" or perhaps varying constants?
> No. The application of the operator to a non-eigenstate doesn't tell you anything
I am suspecting, the cases for the varying disguise might be related to how in the long past, I think acting some operator on a quanutm state is the same as measuring it, but I think this is the first time I realise that not only acting some operator on a non eigenstate is not the same as measuring it (you need the hamiltonian of the system-device to do so), but that any operator correspond to some observable does not tell you anything when acted on a non eigenstate
In linguistics, a tenseless language is a language that does not have a grammatical category of tense. Tenseless languages can and do refer to time but they do so using lexical items such as adverbs or verbs, or by using combinations of aspect, and mood, and words that establish time reference. Examples of tenseless languages are Burmese, Dyirbal, Chinese, Malay (including Indonesian), and in some analyses Greenlandic and Guaraní.
== References ==
== Bibliography ==
Bittner, Maria (2005). "Future discourse in a tenseless language". Journal of Semantics. 12 (4): 339–388. doi:10.1093/jos/ffh029....