What universities have active research groups in Theoretical Condensed Matter?

[Teek]

Hi All,

I'm very close to having to start thinking about what and where my PhD will involve. I'm interested in Theoretical Condensed Matter, (possibly topological superconductors/insulators ) and was just wondering if anyone knows from experience which universities have very active research groups in that field (Or can talk about their experience at a specific university). Do a lot of universities (i.e. Cambridge) have interviews/tests for postgraduate physics applications, or can it be mainly by reference? My current grades at undergraduate are very good and I've done a lot or research work experience in general condensed matter and quantum information, has that sort of thing helped anyone significantly in getting a PhD place?

Thanks.

 

[radium]

Where do you want to do your PhD? In the UK, United States, somewhere else? Admissions depends a lot on the country. I do have some friends who did their undergrad at Cambridge and one of my best friends is currently doing her PhD there. From what I have observed, you usually get your masters beforehand (in the UK the 4th year is a masters usually) before going onto the PhD. You don't need a masters to apply in the U.S. since you will take courses in the first year or two of your PhD. The grad application in the U.S. consists of grades, PGRE scores, and most importantly recommendation letters and research experience.

I actually know quite a bit about the topics you mentioned. Topological phases of matter (this is the much broader subfield that TIs and TSCs fall under) is a very big topic in CMT. A lot of the current work in condensed matter involves studying systems which have some sort of nontrivial topology. Again, this can manifest itself in many ways, not just in TIs/gapped systems with surface states. There are people all over working in this field. The places with the most people (in the US) doing things like TIs/TSCs/FQHE/fractional statistics in those systems are probably MIT, Stanford, Illinois, and UCSB. The list gets much bigger when you start adding topics like spin liquids, some topological phenomena in the cuprates/strongly correlated systems (all of these things have a lot of similarities in many ways). There are also a lot of places which also have great people, just not as many as the places I listed (which all have pretty large departments). Of course one of the first places that comes to mind when you mention TIs is Penn. However, the problem is that while the professor there is one of the very top people in the field, there really aren't any other people to work with.

In regards to admissions, the way to get noticed is to have a lot of research experience, outstanding letters, and relevant coursework. It sounds like you are competitive in these areas. I definitely your work in quantum information will help a lot. Quantum computing is a big topic in the field of topological phases of matter, especially with the experimental observation of Majorana fermions. Another thing that will be considered is your PGRE score. You want to do as well on that as you can. However, if you don't do as well as you, if the rest of your application is very strong it is most definitely not the worst thing that could happen.

 

[Teek]

Where do you want to do your PhD? In the UK, United States, somewhere else? Admissions depends a lot on the country. I do have some friends who did their undergrad at Cambridge and one of my best friends is currently doing her PhD there. From what I have observed, you usually get your masters beforehand (in the UK the 4th year is a masters usually) before going onto the PhD. You don't need a masters to apply in the U.S. since you will take courses in the first year or two of your PhD. The grad application in the U.S. consists of grades, PGRE scores, and most importantly recommendation letters and research experience.

I actually know quite a bit about the topics you mentioned. Topological phases of matter (this is the much broader subfield that TIs and TSCs fall under) is a very big topic in CMT. A lot of the current work in condensed matter involves studying systems which have some sort of nontrivial topology. Again, this can manifest itself in many ways, not just in TIs/gapped systems with surface states. There are people all over working in this field. The places with the most people (in the US) doing things like TIs/TSCs/FQHE/fractional statistics in those systems are probably MIT, Stanford, Illinois, and UCSB. The list gets much bigger when you start adding topics like spin liquids, some topological phenomena in the cuprates/strongly correlated systems (all of these things have a lot of similarities in many ways). There are also a lot of places which also have great people, just not as many as the places I listed (which all have pretty large departments). Of course one of the first places that comes to mind when you mention TIs is Penn. However, the problem is that while the professor there is one of the very top people in the field, there really aren't any other people to work with.

In regards to admissions, the way to get noticed is to have a lot of research experience, outstanding letters, and relevant coursework. It sounds like you are competitive in these areas. I definitely your work in quantum information will help a lot. Quantum computing is a big topic in the field of topological phases of matter, especially with the experimental observation of Majorana fermions. Another thing that will be considered is your PGRE score. You want to do as well on that as you can. However, if you don't do as well as you, if the rest of your application is very strong it is most definitely not the worst thing that could happen.

I am quite set on remaining in the UK for my PhD, and was mainly looking at Cambridge and Manchester's CMT groups, or thinking of staying on at Imperial. I get quite homesick and also wasn't interested in doing a GRE test. I'm currently doing a Summer project on Majorana Fermions in Thin film 111 TSC, but I wasn't aware of its ties with QI, so that's quite cool.

Thanks for your help!

 

[e.bar.goum]

I am quite set on remaining in the UK for my PhD, and was mainly looking at Cambridge and Manchester's CMT groups, or thinking of staying on at Imperial. I get quite homesick and also wasn't interested in doing a GRE test. I'm currently doing a Summer project on Majorana Fermions in Thin film 111 TSC, but I wasn't aware of its ties with QI, so that's quite cool.

Thanks for your help!

I've not gone through the PhD application process in the UK, but I've had friends who have - they all had interviews as well as applications and references. Their interviews were both technical in nature as well as the usual kinds of questions you get in interviews.

 

[radium]

I don't know if you will have a master's by the time you graduate, but I think you will need one.

People in theory don't just work on TIs and TSCs if you are just talking about the garden variety ones with time reversal and spin orbit. TIs especially are more of a materials problem at this point. Also, the Haldane, KM/FKM, Zhang models are non interacting. These days people are interested in interacting systems and fractional statistics for the most part.
In the late 2000s, It was proposed that Majoranas exist on interfaces of strong TIs and S wave SCs. A more promising configuration though is using and iron chain/nanowire connected to a Sc, so that is why people who started working on TIs after 2005 are interested in this. Now people are trying to come up with ways to braid the majoranas and get nonabelian statistics both theoretically and experimentally. Basically you use them to make a qubit. This field is called topological quantum computation. The idea was introduced by Kitaev in the late 90s. The advantage is that when the anyons are separated, they are topologically protected and cannot be destroyed with any local perturbation. This is a solution to the decoherence problems since the transformation properties of the state depends on the topological sector.

I don't know much about professors in the UK in this field, I only know about ones in the U.S.

 

[Teek]

I don't know if you will have a master's by the time you graduate, but I think you will need one.

People in theory don't just work on TIs and TSCs if you are just talking about the garden variety ones with time reversal and spin orbit. TIs especially are more of a materials problem at this point. Also, the Haldane, KM/FKM, Zhang models are non interacting. These days people are interested in interacting systems and fractional statistics for the most part.
In the late 2000s, It was proposed that Majoranas exist on interfaces of strong TIs and S wave SCs. A more promising configuration though is using and iron chain/nanowire connected to a Sc, so that is why people who started working on TIs after 2005 are interested in this. Now people are trying to come up with ways to braid the majoranas and get nonabelian statistics both theoretically and experimentally. Basically you use them to make a qubit. This field is called topological quantum computation. The idea was introduced by Kitaev in the late 90s. The advantage is that when the anyons are separated, they are topologically protected and cannot be destroyed with any local perturbation. This is a solution to the decoherence problems since the transformation properties of the state depends on the topological sector.

I don't know much about professors in the UK in this field, I only know about ones in the U.S.

My next year gives me the Undergraduate Masters that is quite common in the UK. Also my project choice wouldn't be so narrow, as I wouldn't mind a project where I get to study various other aspects of theoretical solid state and the interaction of radiation with matter. I'm looking for quite a computational project, as I very much enjoy the problem solving aspect of it.

Right now I'm looking for Majoranas in a model of a TI/p-wave SC interface but I'm abroad for my Summer CMT project and only have a semi-decent laptop to run simulations, so I'm unable to simulate a large enough system. Hopefully the University I'm working as has some sort of cluster.

The professors in this field in the US are pretty smart from what I've gathered by being here for about 6 months, very driven though. As passionate as I am about this, it feels that I would be working late most nights, however after talking to some PhD students in MIT CMT generally, it seems that would be the case anywhere.

Is it common to do your PhD with the same supervisor that overlooked your Master's project? or at the same University? I've heard it's not so greatly looked at in the US, but I don't imagine many places will have a research environment I feel comfortable in more than Imperial. Its a very closed minded view but I don't to take any chances when it comes to finding a place for my PhD, don't want to get there and I don't like how things are being done.

 

[radium]

In the U.S. you apply directly for the PhD. You can technically get a master's if you have taken enough courses, but it is definitely not required. You may also do an undergrad thesis if you are doing research at your undergrad institution but at a lot of places it isn't a big deal. As far as staying at your undergrad in the U.S., while it is quite common in Europe, I wouldn't recommend it here unless you have a very good reason to. I could have done that and worked with one of the top people in the field you mentioned, but instead I decided I wanted to change environments.

It's true students at the schools mentioned I are very hard working on average. However, it is not true that they are miserable as a lot of people will say (I was told this a lot). I know a lot students from these particular and other comparable schools and most of them are very happy. The environments of these schools have evolved a lot over the past 15 years and students have a lot more support. For example, UChicago has a reputation for unhappy grad students, but from what I have personally seen and one of my best friends experience, people absolutely love Chicago. My friend is the happiest he has ever been, loves the department, his research, etc. It kind of annoys me when people bad mouth these schools since I know that they are not like that from both personal experience and the experiences of close friends.

I'm sure schools like Cambridge may have a similar rep but I think the situation is probably the same over there. If you want to stay in the UK you definitely have wonderful options. I don't know as much about CMT there but from what else I know I'm sure there are really great people. I hear Birmingham is also very well known for CMT.