Dear Diary,
For months now, I've been hoping to figure out what exactly Lucas did to derive the exchange functional. Well, as fate would have it, I just did.
The trick involved taking a double integral in one dimension and noting that the integrand only contained the difference of the two coordinates. The replacement is obvious if you wave your hands! I get the feeling that this is a common trick in the ABCs but it must've flown completely over my head! Li recognized the switch as from a particular class of problems (the Hooke's atom) but man...the math step was not obvious!
In my defense, I did ask Lucas several times for how he did this and nowhere in the notes was this trick. I kept getting an exponential integral. Playing Devil's advocate, however, I should have learned it during the now fifth ABC class I'm in! Again in my defense, somehow this should have been exposed, you'd think. Again playing Devil's advocate: go and do your work! Stop blogging!
Showing posts with label Oh Lucas!. Show all posts
Showing posts with label Oh Lucas!. Show all posts
Wednesday, October 22, 2014
Sunday, July 20, 2014
IPAM Today, IPAM Tomorrow
Dear Diary,
I've received a wonderful opportunity to come and learn from some of the DFT greats here at the Insitute of Pure and Applied Mathematics (IPAM) at UCLA. It really is a great opportunity to meet some of the people whose papers I read and hopefully not mess up too badly in front of them!
Before coming here, I noticed that Lucas sure seems to be popular. The nice graduate student in charge of putting together all of our poster teases says hi to Lucas!* But Lucas didn't know he was that popular at IPAM! Now, there is an identical Lucas running around out there (the original Lucas) whose papers we often misattribute to our own Lucas. But I've learned not to doubt Lucas' charisma, charm, and popularity!
Everything starts tomorrow, so we're to be up at 8am for breakfast. But they haven't announced a menu. IPAMcakes?
*-see the post from a few days ago.
I've received a wonderful opportunity to come and learn from some of the DFT greats here at the Insitute of Pure and Applied Mathematics (IPAM) at UCLA. It really is a great opportunity to meet some of the people whose papers I read and hopefully not mess up too badly in front of them!
Before coming here, I noticed that Lucas sure seems to be popular. The nice graduate student in charge of putting together all of our poster teases says hi to Lucas!* But Lucas didn't know he was that popular at IPAM! Now, there is an identical Lucas running around out there (the original Lucas) whose papers we often misattribute to our own Lucas. But I've learned not to doubt Lucas' charisma, charm, and popularity!
Everything starts tomorrow, so we're to be up at 8am for breakfast. But they haven't announced a menu. IPAMcakes?
*-see the post from a few days ago.
Tuesday, July 15, 2014
The Gettysburg Address
Dear Diary,
This is the year of 2014 which is exactly 88 years after Schrodinger published his famous equation for quantum mechanics. Kieron approached me and Lucas last year about commemorating the event by sneaking in some snippets from Abraham Lincoln's infamous Four Score and Severn (87) years ago speech.
But we didn't publish last year.
Luckily, Thomas-Fermi theory, a commonly used approximation for the kinetic energy that matches up with a uniform gas was published in 1927. That's exactly 87 years ago from this year! So, we thought, why not just honor this other paper?
We did! But the editor's caught us. Kieron was a little disappointed that the reviewers didn't mention it in their reviews, but during the proofing stage, a savvy literature guru at Physical Review noticed it and the Dante's inferno reference placed there by Lucas. So, they would change the wording.
But the joke was still on! They didn't remove enough from the paper to take out the intention! It's still there! Kieron did fess up to the editor's, but one should note that the Physical Review Letter from last year referenced a Tale of Two Cities in the first line.
While the original wording was changed, the world will little note, nor long remember what we say here, but it can never forget what they did here.
This is the year of 2014 which is exactly 88 years after Schrodinger published his famous equation for quantum mechanics. Kieron approached me and Lucas last year about commemorating the event by sneaking in some snippets from Abraham Lincoln's infamous Four Score and Severn (87) years ago speech.
But we didn't publish last year.
Luckily, Thomas-Fermi theory, a commonly used approximation for the kinetic energy that matches up with a uniform gas was published in 1927. That's exactly 87 years ago from this year! So, we thought, why not just honor this other paper?
We did! But the editor's caught us. Kieron was a little disappointed that the reviewers didn't mention it in their reviews, but during the proofing stage, a savvy literature guru at Physical Review noticed it and the Dante's inferno reference placed there by Lucas. So, they would change the wording.
But the joke was still on! They didn't remove enough from the paper to take out the intention! It's still there! Kieron did fess up to the editor's, but one should note that the Physical Review Letter from last year referenced a Tale of Two Cities in the first line.
While the original wording was changed, the world will little note, nor long remember what we say here, but it can never forget what they did here.
Monday, March 17, 2014
March Meeting: Oh, Lucas!
Dear Diary,
A student from Paola Gori-Giorgi gave a talk. At the end, he showed Lucas!
Kieron gave me a tiny assignment that wound up not working out, but I had to sort through this strictly correlated electron business some weeks ago. If one takes the the electron-electron potential's coupling to infinity (and tunes the external potential to keep the density the same), then you get very interesting physics where electrons are localized. It's tough to solve for the co-motion functions that tell you how the electrons move around, though.
Doing so, you can address strongly correlated materials.
Anyway, Lucas showed up. I saw it. That was cool.
A student from Paola Gori-Giorgi gave a talk. At the end, he showed Lucas!
Kieron gave me a tiny assignment that wound up not working out, but I had to sort through this strictly correlated electron business some weeks ago. If one takes the the electron-electron potential's coupling to infinity (and tunes the external potential to keep the density the same), then you get very interesting physics where electrons are localized. It's tough to solve for the co-motion functions that tell you how the electrons move around, though.
Doing so, you can address strongly correlated materials.
Anyway, Lucas showed up. I saw it. That was cool.
Thursday, March 13, 2014
It's my time to shine!
Dear Diary,
Kieron has deputized me in the quest to put out a paper by the end of the month. It is to be my top priority. But, as they say, first is the worst--second is the best--and third (in my priority list this would be working on a separate paper) is the one in a polka dot dress.
My first task was to set up the appropriate folders for the draft. This involved finding all the references Lucas had put into the paper...all 86 of them! So, I went through each of the references, found their pdfs and then renamed them all to the classic Burke short-hand.
The last letters of each author (up to four) appear in capital letters followed by the year. If two such papers are named identically, the second earns a "b" at the end of it (and so on through the alphabet if there are more).
As an example, if Drs. Who and Hyde appear on a paper from 1901, then the shorthand would be WH01. As a further example, for hyphenated names where you could have two possible choices, you only retain one of the letters. So, for Gori-Giorgi, you obviously take the "G".
Kieron has deputized me in the quest to put out a paper by the end of the month. It is to be my top priority. But, as they say, first is the worst--second is the best--and third (in my priority list this would be working on a separate paper) is the one in a polka dot dress.
My first task was to set up the appropriate folders for the draft. This involved finding all the references Lucas had put into the paper...all 86 of them! So, I went through each of the references, found their pdfs and then renamed them all to the classic Burke short-hand.
The last letters of each author (up to four) appear in capital letters followed by the year. If two such papers are named identically, the second earns a "b" at the end of it (and so on through the alphabet if there are more).
As an example, if Drs. Who and Hyde appear on a paper from 1901, then the shorthand would be WH01. As a further example, for hyphenated names where you could have two possible choices, you only retain one of the letters. So, for Gori-Giorgi, you obviously take the "G".
Monday, February 24, 2014
Oops! Should have known that (#328/420,870)
Dear Diary,
Yikes. Li and I have been running some binding curves of H2. Thing is, they don't look like the binding curves of H2 that either John or Lucas published in their papers. The dips of our curves are located around zero separation.
But the dips of those published figures are around 2-something! A conundrum!
Lucas set me straight, like always. By, as he says, going back to basics. The regular DFT calculations don't include nuclear-nuclear repulsion. So, when you calculate the electronic density, the atoms are fixed. If you add in the nuclear-nuclear repulsion term, then you get the dip at a higher number. This is where the molecule was bound if we did a calculation where the nuclei were allowed to move around.
These turn out to be accurate (depending on what flavor of DFT you use), but that's exactly what we're trying to fix! Trying to calculate these properties can help with a lot things like climate models and other things! Yay!
Yikes. Li and I have been running some binding curves of H2. Thing is, they don't look like the binding curves of H2 that either John or Lucas published in their papers. The dips of our curves are located around zero separation.
But the dips of those published figures are around 2-something! A conundrum!
Lucas set me straight, like always. By, as he says, going back to basics. The regular DFT calculations don't include nuclear-nuclear repulsion. So, when you calculate the electronic density, the atoms are fixed. If you add in the nuclear-nuclear repulsion term, then you get the dip at a higher number. This is where the molecule was bound if we did a calculation where the nuclei were allowed to move around.
These turn out to be accurate (depending on what flavor of DFT you use), but that's exactly what we're trying to fix! Trying to calculate these properties can help with a lot things like climate models and other things! Yay!
Wednesday, February 19, 2014
We ride together, we derive together, bad boys for life
Dear Diary,
I had an individual meeting that got very hectic! At first, I came in at the end of Li's meeting and sat down to wait my turn. Turns out, they were just getting to my and Li's collaboration. Li explained some details and just about as I was to being, Justin arrived!
Justin didn't have much, so Kieron and he postponed, giving me more time (not always good!). So, I went to the board and began discussing a last figure that Lucas and I were making. Then, who should call but Lucas!
Kieron and Lucas discussed some items over Skype when who should call but John! He said he missed my voice! So, Kieron put his tablet and computer facing each other so that John and Lucas could chat for a bit. Then Kieron wanted Li back up to be there when Kevin arrived. Kevin didn't arrive, but when Kieron called the office to get Li, an old voicemail from Lucas answered!
Now, I'm used to having chaotic meetings. They happened with my old advisor all of the time. Kieron is busy a lot of the time and I'm able to find other things to fill my schedule with if I can't get all of my answers in the individual meeting window. So, I've turned my attention to matters I can get done and stay productive (including a project that Kieron doesn't even know about yet!).
I had an individual meeting that got very hectic! At first, I came in at the end of Li's meeting and sat down to wait my turn. Turns out, they were just getting to my and Li's collaboration. Li explained some details and just about as I was to being, Justin arrived!
Justin didn't have much, so Kieron and he postponed, giving me more time (not always good!). So, I went to the board and began discussing a last figure that Lucas and I were making. Then, who should call but Lucas!
Kieron and Lucas discussed some items over Skype when who should call but John! He said he missed my voice! So, Kieron put his tablet and computer facing each other so that John and Lucas could chat for a bit. Then Kieron wanted Li back up to be there when Kevin arrived. Kevin didn't arrive, but when Kieron called the office to get Li, an old voicemail from Lucas answered!
Now, I'm used to having chaotic meetings. They happened with my old advisor all of the time. Kieron is busy a lot of the time and I'm able to find other things to fill my schedule with if I can't get all of my answers in the individual meeting window. So, I've turned my attention to matters I can get done and stay productive (including a project that Kieron doesn't even know about yet!).
Thursday, February 13, 2014
What is dreamed and math that should never be (part 3)
From Lucas!
"You can also diagonalize large matrices without explicit
diagonalization, and it's also related to the inverse. The key is to
use the Green's function G(z) = (z S - H)^{-1}, defined for the
generalized eigenvalue problem H psi = S psi E. Taking a contour
integral C in the complex plane which encloses the eigenvalues you want,
you can get the density matrix rho = -1/(2 pi i) INT[z on C] G(z),
which is essentially psi psi^T. Go complex analysis and residue
theorems!
There's a neat method which avoids the full inverse
and approximates the contour integral nicely, and it's super
parallelizable. I think Zhenfei or Zenghui gave it at a previous group
talk. Or maybe John. You can find it at <a href="http://arxiv.org/abs/
Wednesday, November 20, 2013
E tu, Macro?
Dear Diary,
Oh, Lucas! You left me with an unfinished paper (thank you, sort of). Normally, I would be thrilled to help you get another publication, but you have so many macros in your Latex documents to make things so much simpler to type up. I'm from the school of type everything out long hand!
So, I made a new figure and then tried to implement it into the tex file. You know
\begin{figure}
\includegraphics[width=\columnwidth]{newpic.pdf}
\caption{Figures. It's a figure. \label{fig:itsa}}
\end{figure}
but then it didn't compile! I tried and tried (I even removed the above to see if it worked and it did!) until I removed a different figure and somehow it compiled! It turns out that one of the macros later on was busted and this mysteriously revealed itself when I added a new figure.
So, there! Don't use macros! They only make your life easier! I should go tell Justin to stop using macros to make changing symbols easier if he wants a switch and just go do everything by hand every time he makes a switch!
Oh, Lucas! You left me with an unfinished paper (thank you, sort of). Normally, I would be thrilled to help you get another publication, but you have so many macros in your Latex documents to make things so much simpler to type up. I'm from the school of type everything out long hand!
So, I made a new figure and then tried to implement it into the tex file. You know
\begin{figure}
\includegraphics[width=\columnwidth]{newpic.pdf}
\caption{Figures. It's a figure. \label{fig:itsa}}
\end{figure}
but then it didn't compile! I tried and tried (I even removed the above to see if it worked and it did!) until I removed a different figure and somehow it compiled! It turns out that one of the macros later on was busted and this mysteriously revealed itself when I added a new figure.
So, there! Don't use macros! They only make your life easier! I should go tell Justin to stop using macros to make changing symbols easier if he wants a switch and just go do everything by hand every time he makes a switch!
Thursday, November 14, 2013
Don't pull the eject button!
Dear Diary,
I had to run my first meeting in place of Kieron. Really, I found it was easy. I let everyone else do most of the talking. The group wisdom is usually best here and kept the pressure off me.
We were going over abstracts for the American Physical Society meeting in March. I put up mine first because I'm the newest, and it went over well! It only took 45 minutes to iron out the kinks and make sure we broke everything down didactically! I think everyone else's benefitted from it because it didn't take as long! I actually think we're going to have a golden set of abstracts for the APS.
Guo is sitting in with us for a few weeks since he's new to the program and pointed out that I didn't add any firm conclusions. I could add a few points to the content; however, I don't have any yet...I'll have to work hard so I'll have something to say in Colorado! I showed it to Kieron beforehand, and he could only say good things about how broad the abstract is. Huzzah!
When I finally submitted, I had to cut it even further because the new affiliations for Miles and Lucas (especially Lucas') put me over the limit. APS gives you a little line that you can't go under, so beware. I can write as much as I want with you, though, diary!
Oh, Lucas! I finally fit your dervatives! Yay! I'll add them to the paper in an appropriate place. Don't pull the eject button too soon and submit, Lucas!
I had to run my first meeting in place of Kieron. Really, I found it was easy. I let everyone else do most of the talking. The group wisdom is usually best here and kept the pressure off me.
We were going over abstracts for the American Physical Society meeting in March. I put up mine first because I'm the newest, and it went over well! It only took 45 minutes to iron out the kinks and make sure we broke everything down didactically! I think everyone else's benefitted from it because it didn't take as long! I actually think we're going to have a golden set of abstracts for the APS.
Guo is sitting in with us for a few weeks since he's new to the program and pointed out that I didn't add any firm conclusions. I could add a few points to the content; however, I don't have any yet...I'll have to work hard so I'll have something to say in Colorado! I showed it to Kieron beforehand, and he could only say good things about how broad the abstract is. Huzzah!
When I finally submitted, I had to cut it even further because the new affiliations for Miles and Lucas (especially Lucas') put me over the limit. APS gives you a little line that you can't go under, so beware. I can write as much as I want with you, though, diary!
Oh, Lucas! I finally fit your dervatives! Yay! I'll add them to the paper in an appropriate place. Don't pull the eject button too soon and submit, Lucas!
Monday, November 4, 2013
Obey your Master(.bib)
Dear Diary,
Wow! I never knew I could be that productive! I just successfully eradicated all traces of malfeasance in the group's Master.bib file by spending two hours straight parsing errors!
Master.bib is the Bibtex file that the group uses to enact it's evil plot to collect every reference that's ever been referenced! (Current unique references: 2344) Maybe I already explained this to you, diary, I can't remember because my head hurts...
Anyway, it appears that much more head hurting occurred in previous generations of Burke students. The file wouldn't compile for a myriad of reasons:
1) "%" signs must be listed as "\%" for Latex to work
2) Oh, Lucas! You can't press return in the middle of an abstract! Latex thinks it's a new line!
3) Curly parentheses are critical
4) The numbers 1998 and 24 are completely different. Even scarier: Latex knows the difference between a year and a TV show. I have to make sure I keep that straight and not lose track of the date! Oh no! It's daylight savings time apparently!
Anyway, it's done. Enjoy, everyone.
Wow! I never knew I could be that productive! I just successfully eradicated all traces of malfeasance in the group's Master.bib file by spending two hours straight parsing errors!
Master.bib is the Bibtex file that the group uses to enact it's evil plot to collect every reference that's ever been referenced! (Current unique references: 2344) Maybe I already explained this to you, diary, I can't remember because my head hurts...
Anyway, it appears that much more head hurting occurred in previous generations of Burke students. The file wouldn't compile for a myriad of reasons:
1) "%" signs must be listed as "\%" for Latex to work
2) Oh, Lucas! You can't press return in the middle of an abstract! Latex thinks it's a new line!
3) Curly parentheses are critical
4) The numbers 1998 and 24 are completely different. Even scarier: Latex knows the difference between a year and a TV show. I have to make sure I keep that straight and not lose track of the date! Oh no! It's daylight savings time apparently!
Anyway, it's done. Enjoy, everyone.
Wednesday, October 30, 2013
Far West Regional APS Meeting (Part III)
Dear Diary,
Yikes. I felt like I did not do my best presentation during the group meeting. I succeeded in getting nervous throughout the first third of the presentation. Hopefully, that's the end of being nervous.
The group had really good suggestions. I need to express in plain language the intent of my talk right at the beginning instead of implying it. People had trouble knowing what to expect. If given a scaffold at the beginning, diary, the audience will be able to build the presentation with you during the talk.
And I spent all week on preparing for the conference (as well as other minor duties)! It's tough work preparing and I want to make sure everything is in order...well, without spending months on it. I better get moving on everything once I get back, and I need to remember to take some conference notes, report on what I see, and talk to three professors.
Oh no, Lucas! I told Lucas I couldn't get the derivatives fit this week like he wanted but that didn't happen! He moved off to a post-doc taking his expertise with him. Worst of all, now when I have a meeting with Kieron, I don't have my Lucas crutch! Yikes!
Yikes. I felt like I did not do my best presentation during the group meeting. I succeeded in getting nervous throughout the first third of the presentation. Hopefully, that's the end of being nervous.
The group had really good suggestions. I need to express in plain language the intent of my talk right at the beginning instead of implying it. People had trouble knowing what to expect. If given a scaffold at the beginning, diary, the audience will be able to build the presentation with you during the talk.
And I spent all week on preparing for the conference (as well as other minor duties)! It's tough work preparing and I want to make sure everything is in order...well, without spending months on it. I better get moving on everything once I get back, and I need to remember to take some conference notes, report on what I see, and talk to three professors.
Oh no, Lucas! I told Lucas I couldn't get the derivatives fit this week like he wanted but that didn't happen! He moved off to a post-doc taking his expertise with him. Worst of all, now when I have a meeting with Kieron, I don't have my Lucas crutch! Yikes!
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