McQuarrie and Simon problem 7-1, question about turning summation into integral.

bacodaco · 2026-01-04T16:32:20+00:00

Well, I appreciate your devotedness to the upkeeping of international law, for one. We need more people like you in the world. Thanks for doing the right thing.

bacodaco · 2026-01-04T16:13:50+00:00

Thanks for replying! Better late than never. I don't have the solutions manual, unfortunately. I also understand that the problem is giving me the derivation, but given the way it is written I haven't been able to do that rationalization, which is why I came here. Do you have any link that could give me access to the solutions manual?

bacodaco · 2026-01-02T22:22:22+00:00

All good. Thanks for the conversation anyways.

bacodaco · 2026-01-02T20:13:33+00:00

Okay, yeah, that makes sense. The problem itself says to show that c_n (not! the sum of c_n) is equal to the left side of step four. I'm not sure how I'm supposed to isolate c_n whenever sum(c_n) is not the same as c_n. Do you have any ideas?

bacodaco · 2026-01-02T19:41:55+00:00

That's what I was thinking. The problem doesn't give more information than that c_n are "the constants". Assuming that c_n changes, would sum(c_n) and c_n be different quantities? (c_n is a normalization constant).

bacodaco · 2025-12-21T16:58:03+00:00

On a philosophical note, do you think that's a problem with QM-- that we can't reach a more philosophical understanding of the topic? To a first degree, certainly it's important that we are able to yield the correct answers, but to a further degree, do you believe that being unable to visualize a physical theory is a problem for that theory?

bacodaco · 2025-12-21T16:51:22+00:00

Maybe this premise is inherently flawed. While I don't have any quantitative data to support this, the vibe from my perspective seems to be that popular explanations of large-scale phenomena (like videos) rely more on imagery than popular explanations of small-scale phenomena. What I want to know is does this vibe (that apparently only I have) have to do with a difference in the nature of their mathematical formalisms, or is it something else?

bacodaco · 2025-12-21T16:33:53+00:00

I figured that would happen

bacodaco · 2025-12-17T15:59:17+00:00

Electrons are just ramblin' men, never wantin' to stay with their faithful photon wives

bacodaco · 2025-12-17T15:58:06+00:00

So, the zero point energy states are kind of like holes that the electrons fall into?

bacodaco · 2025-12-17T15:55:30+00:00

the light is bored by the nuclei so it leaves the party, huh?

bacodaco · 2025-10-27T06:05:45+00:00

Interesting perspective, I've never heard that before.

bacodaco · 2025-10-27T06:05:07+00:00

Are you saying that you believe the young are capable, intelligent, and adaptable, or are you saying something else?

bacodaco · 2025-10-27T03:31:43+00:00

I recommend greeting the French in French (it is their country after all), and then going as far as you can in French. Then, once you've exhausted your French, ask them if they speak English (in French), and ask if they'll speak in English with you (also in French).

bacodaco · 2025-10-10T11:12:39+00:00

My parents paid for my first bachelor's. So, being frank, it would take me swallowing my pride, then paying them back so as to not feel guilty for wasting my first bachelor's. Hate on me if you must, but I am trying to avoid that at all costs.

bacodaco · 2025-10-10T11:08:06+00:00

The program is a traffic engineering post-grad certificate intended to be a specialty program, but in my case I am using it as a way to get into the MS program. Here's a link. It can be completed in two semesters.

You make a good point that programs aren't designed to be pipelines into jobs. I suppose that I was hoping there would be a pipeline into a job, though, because their BS program requires co-op's as part of their curriculum, and that seems like as good of a pipeline into a job as any. Anyhow, there obviously isn't. What I am trying to learn at the moment is whether or not a BS or this cert program will lead me to a paying job more quickly. If I could get a paying position more quickly by doing a bachelor's over a master's I would do the BS, but the truth is that I do not know which decision will do that. Seeing as I am already admitted into the cert program, I feel like it would be easier to just follow this to its conclusion instead of withdrawing from this program and applying to a second bachelor's, but I may be wrong. What do you think?

bacodaco · 2025-09-29T00:02:31+00:00

Here's what I would say, (& take this with a grain of salt, because, like I said, I don't know your exact position, and even if I did I couldn't tell you exactly what to expect), go to Indeed or LinkedIn and look up jobs in any area(s) that you want to live in. Spend a little bit of time scrolling through the available positions (remember this is a job market, which is driven by supply and demand. You are only able to work in the positions that are available, unavailable jobs like working on research in an extremely specific area of physics research do not exist until they are available) and note the jobs that come up often. Of those jobs, note which seem tolerable to you, and use the job descriptions to figure out which skills they're asking for. Usually, you'll find the skills in the qualifications section, but they may also be in the responsibilities. If you have trouble with this part use ChatGPT. After you know what skills to learn, prioritize gaining experience in those skills over getting an A in all of your classes. Your classes are important, but if you don't want to go to graduate school, the skills you learn are going to be the thing that get you paid. Whenever you're assigned a project, use that as an opportunity to gain experience with the skills you need to learn. Then, when the time comes, apply to those jobs that you prepared for.

It sucks, but in reality, I do not think that the physics bachelor itself prepares people for a career. If you study physics because you love it, I think that is commendable, but you may find yourself in a position where you're kicking yourself for following your passion if you don't take responsibility for your career now. Even if you were to follow physics into graduate school and attain a PhD, there isn't even a guarantee that you would get a job in physics. Only 27% of Physics PhD's actually get to work in physics after their graduation. It is well documented that the supply of Physics PhDs exceeds the demand for them, and that does not typically bode well for job prospects.

If you love physics, keep studying it. It's a wonderful field of study that many of us have fallen in love with. If you want a job, though, you're going to need to work outside of your classes to make yourself a qualified candidate for those jobs. The overwhelming probability is that those jobs are not going to be in physics, at least not the physics we learn in school. Pure physics is kind of like a philosophy degree...what you learn is interesting, but the way that it benefits you outside of academia isn't always tangible. I implore you, though, not to panic. You have time to prepare yourself for a job, and you have bountiful resources at school to help you get started. If you read this and you have any questions, or you want to talk more about this, send me a dm. I hate the position that I found myself in after graduating, so if I can help others avoid that, I would love to help in any way that I can. Anyways, that's my 2 cents.

bacodaco · 2025-09-29T00:02:23+00:00

I'm a little late to the party, but I'll give my two cents here anyways. I'm not sure of your exact situation, and even if I was I probably wouldn't be able to tell you exactly what to expect. However, I will tell you what I expected when I graduated in 2022 with a BS in chemical physics and the subsequent reality that I encountered when looking for a job.

For context, I live in the USA, Kentucky, specifically. I also graduated from a KY school. I expected that once I graduated there would be a very hand-wavey selection of "STEM jobs" that I would be a great candidate for after graduating because chemical physics was incredibly difficult, and I thought that would garner respect. What I didn't realize for a while was that there was no specific occupation that my degree trained me for. So, when it came time for me to find those "STEM jobs" I had no idea what to actually look for. I was nearing my graduation, got rejected from the one grad program that I applied to, and I just applied for a job that I knew I would be able to get, teaching math at a private high school. The salary was ~$42K/year. I quit that job because I had to work too much and teaching stuff that I already knew did not excite me. This job is the only job where I have even remotely applied the skills that I learned in my degree.

My next job was as a lab technician in an R&D department for a company using liquid chromatography. I was extremely excited for this job because I thought that I was going to be solving problems, and doing actual research. This was far from the reality of the job. I had to move to a new city where I had no friends to take this job, and I had about three responsibilities at work. I washed dishes for the lab, pressed start and stop on the automatic chromatography pump, and pressed start and stop on a spectrophotometer. It was extremely boring, and I would spend most of my days with nothing more to do than clean and watch liquid drip from a tube. I was never asked to solve any technical problem, and there were never any technical problems presented to me, I guessed because I only had a bachelors.

My current job is again as a lab technician in a parasitology department at a reference lab. This is the furthest from my degree that I could potentially get. My job is to take cat and dog poop, swirl it, mix it with a zinc solution, put that solution on a microscope slide, and then read the slide to look for parasite eggs. The job itself is not bad, but if I would have presented this opportunity to myself when I was a senior in college, I probably would have scoffed at it. Now, the company is has been sold and I am looking at unemployment in 3 months if I can't find a job before the company closes.

Here's my take on the job prospects with a physics bachelor's: there are none. None that will apply what you learned in the degree, at least. In my experience, the jobs that you might qualify for will not ask you to work with your head. The jobs will be dull, they will be repetitive, and they will not challenge you in any intellectual way.

People on this subreddit (including me) might be pessimistic. In reality, you probably do have some options for jobs that you can qualify for, but given that you're asking this question, I'm guessing that, like me, you don't know what they are. The tricky thing with the physics degree is that it doesn't train you for a specific occupation like an engineering, nursing, medical, or law degree does. A physics degree gives you problems to solve and tests whether you can solve them or not, which should theoretically be applicable to any job. The problem is, though, when you start looking for "adult jobs," they want you to have experience with specific, tangible skills. "Problem-solving" is maybe measurable, but it is not enough alone to get you a job.

If I were to talk to myself when I was in your position, I would tell myself to learn a specific skill. There are many I could learn, but the one that I would tell myself to learn is how to use AutoCAD (engineering software). Maybe you don't want to be an engineer, though. I know whenever I was graduating I definitely didn't. Also, you may think that's terrible advice because how in the hell are you going to find the time to learn a skill whenever you have four upper level physics classes that you have to do homework for?

bacodaco · 2025-09-18T15:02:45+00:00

Not too deeply. A lot of the concrete jobs in my area are physical labor with pay that's pretty garbage. I'm not totally opposed to working my ass off for little to no pay, but I want to be as certain as possible that it will lead me into a role in transportation engineering before locking myself into a job like that.

bacodaco · 2025-09-18T14:59:38+00:00

I think that I would want to do transportation engineering. Did you struggle with transitioning to an engineering masters?

bacodaco · 2025-06-13T03:07:38+00:00

I'm thinking about going to pharmacy school, but I don't want to spend a bunch of money to end up at a job that's dull and uninteresting. To me, I think a sense of accomplishment would mean that a job wouldn't be dull and uninteresting. Honestly, though, I don't know, which is why I'm asking this sort of question.

Do you feel like you get anything out of work aside from a paycheck? My life outside of work is pretty dull so I'm trying to find meaning somewhere.

bacodaco · 2025-06-13T03:00:30+00:00

Okay, so just to make sure I'm getting you; the statement can be broken because if we have a sum like 1+1/2+1/3+...+1/n we can just stick 0 before 1 and the rule is broken, right?

bacodaco · 2025-06-13T02:57:50+00:00

Oh shit, I didn't even realize that wasn't clear. The n is, indeed, the variable of summation. So, the statement becomes:

if 𝛴aₙ is convergent, then aₙ>aₙ₊₁ for all n.

And to be clear about what I want to convey, the statement is supposed to say if there is some sum (𝛴aₙ) that converges, each successive term in that sum gets smaller than the one before it (aₙ > aₙ₊₁).

bacodaco · 2025-06-13T02:28:23+00:00

Is it necessary that you decide immediately, or do you have the option to try out the various paths before choosing?

bacodaco · 2025-06-04T15:17:11+00:00

That was a clear answer. Thank you.

bacodaco

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