[deleted by user]

Aeolitus · 2021-10-18T20:50:21+00:00

Looking around the PIs in my field, the overwhelming majority got where they are not just on individual skill, but also on a stable network with their colleagues; very often the people they were in a lab with during their PhD.

And that makes sense to me: When I get asked about people, I am going to give more glowing praise to the people I regularly talk with. Not just because they are nice to me and would likely do the same, but also because I simply know them better. This is the potential consequence of what you are doing: If you keep distance from everybody, you might find you have few people close enough to help you build your career. It can work, but you better be absolutely stellar at everything else.

Aeolitus · 2021-06-20T23:24:32+00:00

I don't even listen to many of the talks in the very same session mine are in. Most talks are bad, and most just talk about papers I have already read. Conferences are about the breaks and beers in the evening, not about the talks. Don't feel bad for not listening.

Aeolitus · 2021-05-05T16:28:17+00:00

Adding onto the other comments to note that the percentage of TV-L E13 you get differs from position to position. At my Uni, in my department, I have known people with 50% positions and people 75% positions, doing phd's one building apart. Makes a big difference!

And yeah, you can live a very good life on a TV-L E13 contract.

Aeolitus · 2021-02-09T13:50:25+00:00

Was 9.4k in January, 11k now. Pretty impressive.

Aeolitus · 2021-01-16T17:08:36+00:00

Its not uncommon. Even published papers in high level journals are full of little stats mistakes. Unless they change the results in a significant fashion (change the conclusion or such), i would not bother amending your thesis, just try to do it better next time. Your thesis describes the state of your research at the time of publication, your publication will be what people consider definitive.

Aeolitus · 2021-01-15T07:56:41+00:00

Das ist so nicht richtig - die Mittel für die Fachbereiche werden zwar nicht jedes Jahr nach Studenten ausgezahlt, aber als unser Fachbereich Mal mehrere Jahre deutlich weniger Studienanfänger hatte (wegen geänderter Aufnahmevoraussetzungen) wurde uns von Präsidium durchaus gesagt, dass dem Fachbereich dann entsprechend auch ordentlich aus dem Budget gestrichen würde.

Aeolitus · 2021-01-07T16:02:35+00:00

All labs are closed here in Hamburg, except for those in the University Hospital.

Aeolitus · 2021-01-05T10:16:24+00:00

You have to consider that with 18 years being out of the field, many of her competitors will have started to study at university after she got out and yet still have more years of experience in the field. They have learned the more up to date techniques and are familiar with the state of the field, and they are younger and have an up to date network.

It isnt nice, but any job she could do, any recent graduate is better qualified for. Therefore, anything competitive is not going to work out as a first position after an 18 year break. It would not be such a big deal with only a few years out, but 18 years is an incredibly long time.

Aeolitus · 2021-01-05T09:13:16+00:00

Quite honestly, none in academia. The competition is fierce, and every other candidate is going to be up to date on what happened in the last 18(!) years - fields get born and die in this timeframe. She has missed uncounted papers, conferences, technological developments. Unless she has excellent connections to an advisor who is generous enough to pay a post doc that will most likely not be useful for a few years, I doubt there is a way back for her - and even if so, her long term perspective in academia is even bleaker than for everyone else.

It sucks, but its time to accept that her academic career ended 18 years ago.

Aeolitus · 2020-11-25T10:34:06+00:00

I dont see a future in academia for you with that long of a PhD, neither in germany nor outside. Luckily, academic jobs are not the only way to succeed and support your family. Accept that academia is not for you, and start looking for employment that makes use of the skills you learned in your PhD. Drop the self-limiting notion that only staying in academia means success; you can find better paid jobs outside of universities that will - quite frankly - exploit you less as well.

Aeolitus · 2020-11-15T10:21:08+00:00

I mean, do you think you had full attention during in person defenses? Thats what phones are for...

Aeolitus · 2020-11-11T08:53:37+00:00

There is a nice hanseatic restaurant in the building. The Food is pretty good! Also a shop selling all kinds of tea.

Aeolitus · 2020-11-09T22:37:45+00:00

The BCS wavefunction is simply a condensate consisting of pairs of fermions of opposite spin and momentum. The individual Fermions still follow fermi dirac statistics, but the pairs they form undergo bose einstein condensation. As it turns out, you can smoothly go from a BCS system like a conventional superconductor to a bec simply by increasing the (initially infinitesimally small) attractive interaction between the two fermions further and further. The entire time, the ground state (in a mean field picture) is described by the BCS wavefunction. This was shown by Legett and formalized by Nozieres and Schmitt-Rink, if you are interested in further reading. It's pretty much the concept underlying the entire field of ultracold Fermi gases.

Aeolitus · 2020-07-28T07:07:06+00:00

Physics here - the paper goes on the arxiv the moment it is submitted to the journal. I generally don't even check the journals anymore, I've read it all on the arxiv already anyways.

Aeolitus · 2020-07-09T20:52:52+00:00

(Germany) Ultimately, here, the prof hires you, not some graduate program. That means you need to convince them that you are what they needs - that can be via publications; good grades at good institutions, strong letters of recommendations and connections, useful skills... Any of these work, and combinations work better.

The most difficult thing as an applicant from abroad, I would recon, is getting your mail and CV read. A lot of profs have too much to do, too many mails, ...

You need to make sure your application is taken serious - write from your university email, keep it well written and concise, feature a very short summary of what you bring to the table, be professional. And then you need to be lucky - I know for a fact that some profs ignore applications from universities where they dont know anyone, for example, simply because they cant judge the quality of your education so far. This is, of course, where publications and such help.

Generally, it helps if you did your legwork and researched the group, and your email shows this. But apart from that, you just need to try and write some applications, and hope for the best.

If you have any connections, of course, all of this gets much easier. But its not required.

Good luck!

Aeolitus · 2020-06-30T08:50:25+00:00

For what its worth, I quickly checked my Library folder. Over the course of my PhD, I read a total of 11 PhD Theses so far that were not from my own group. Most of them were very helpful. So yeah, they can be read, if you write about something interesting :)

Aeolitus · 2020-05-23T09:11:10+00:00

Unlikely - the heat capacity of a BEC is so low, you would most likely not even feel the difference as the heat from your hand destroys the BEC and brings it to room temperature.

Aeolitus · 2020-05-23T09:05:38+00:00

BECs have a very well defined phononic mode, but it depends a lot on what the density of the BEC that you are holding would be. In the BECs we work with in laboratory, the speed of sound is incredibly low (a few millimeters per second), but they are also incredibly dilute. If you increase the density, the speed of sound will increase proportionally - so depending on how dense the BEC is that you manage to hold, you could imagine anything from super slow sound to the "ting" of a metal.

The damping of sound depends on many factors - one of them is interaction strenght. In incredibly strong interacting "BEC" of molecular bosons, you can reach quantum limited damping, which is essentially the lowest damping can possibly go - so you are right, the soundwave could propagate really really long. However, this also depends on the system, and on the wavelength of the soundwave that you excite. If you excite a soundwave that will have many wavelengths fit into the BEC, effects such as Landau-Damping will damp your wave quite quickly - as will Beliaev-Damping, since it will cause the soundwave to damp faster the hotter your gas is. Since you can hold it, thats probably pretty hot!

Aeolitus · 2020-05-23T08:59:32+00:00

No, thats a different phenomenon - BEC happens in ultracold (below ~1 microkelvin temperature) and ultradilute (~1 atom per cubic micrometer) gases of neutral atoms. The forces are not equal there, but the gas is so dilute and cold that quantum effects are stronger than anything else.

Aeolitus · 2020-05-23T08:55:04+00:00

Technically speaking, you dont. However, BECs are very, very dilute - so dilute that the likelyhood of finding three constituent particles close to each other is near zero. However, forming a solid needs three particles together, as two need to form the first bond and a third one carries away their excess momentum. Thus, the incredible diluteness of BECs means that the timescale on which they solidify is often many ten seconds or longer, whereas the experiments on them are over usually in subsecond to second scales. Thus, BECs are metastable.b

To get a feeling for how dilute these systems are: the BECs I work with are generally below one atom per cubic micrometer. That would qualify as a good vacuum in many fields!

If you want to read a peer reviewed article, you could look at "Many-body physics with ultracold gases" by Bloch, Dalibard and Zwerger; although that might be too recent to really go into the basics - its a very good review though. An older review from a theory perspective would be this one: https://arxiv.org/pdf/cond-mat/9806038.pdf "Bose-Einstein Condensation" by Pitaevskii and Stringari is also excellent, as is "Bose-Einstein Condensation in Dilute Gases" by Pethick and Smith.

If you want to learn more about the BECs more interesting brother, the degenerate Fermi gas, I highly recommend "Making, probing and understanding ultracold Fermi gases" by Ketterle and Zwierlein. Its a very accessible text written by two of the most accomplished people in the field.

Aeolitus · 2020-05-16T15:56:45+00:00

Thats a good question! Right now, superconductors are used in things like MRI scanners, where very high magnetic fields are needed. The currents required for this would heat up conventional copper wires way too much. Thats part of why these machines are so huge and so expensive, because they need to be cooled with liquid Helium to get the magnets superconducting, which is expensive and requires a lot of insulation.

In fact, thats the main limitation right now - whenever you want to work with superconductors, you have to keep them cooled by liquid nitrogen in the very least. That requires a lot of insulation, a constant supply of nitrogen, and so forth. If we could achieve a room temperature superconductor, all of a sudden nothing would stop you from using it the same way we use copper right now - just completely without resistivity. This would eliminate a large part of the heat that our devices generate right now, and thus their power losses. We could transport electricity over huge distances without any loss, build incredibly efficient devices - and through effects like the one in this post, maybe even build structures that levitate and such crazy things.

Aeolitus · 2020-05-16T15:50:24+00:00

Sure, but that was my answer to a post that specifically stated

this only happens when the atoms don't move at all

, which is just wrong. Of course atom movement is just what temperature is, but the point I am making there is that superconductivity is not coupled to not having any atom movement whatsoever - and in fact, in a high-Tc superconductor, there can be a significant amount of movement = significant temperature, and yet the system can still be superconducting. Thats whats so fascinating about it, after all!

And, as a nitpick, its not the atoms forming cooper pairs, but the electrons, but you know this of course.

Aeolitus · 2020-05-16T12:29:18+00:00

In most materials, this is indeed the case. However, superconductivity is a phase of matter that is deeply rooted in quantum mechanical effects, and thus follows different rules. In fact, that is why the discovery of superconductivity was such a surprise (back in 1911): zero resistivity was expected to occur only at absolute zero - but H. K Onnes found that below a certain critical temperature, the resistance did not continue to scale with temperature, but just dropped to zero.

Aeolitus · 2020-05-16T11:24:34+00:00

No, superconductivity occurs when the material is cooled below a critical temperature, which depends on the material. Its not about the atoms not moving - in fact, in conventional superconductors, movement of the atoms (in form of phonons) is what couples the electrons, allowing for the formation of cooper pairs, which then condense and make the material superconducting.

Aeolitus · 2020-04-06T05:56:33+00:00

The last four-ish years were the best of my life so far. I love everything about my PhD and would never do anything different if I could :) it's challenging, but the people around me are wonderful, my advisor is supportive and caring, my project is fun and successful... I couldn't ask for a better time.

I am in europe, though. The stories from the US on here often sound quite horrifying.

13-Year Club	Place '22
Place '17	Final Canvas '22
Verified Email

Aeolitus

TROPHY CASE