Recent content by chuckschuldiner

Hi guys, In quantum mechanics, the virial theorem for a system in its ground state is proved by a very nice scaling technique (Nielsen and Martin, PRB, 1985). I was trying to do something similar in classical mechanics and arrived at the virial theorem but i am not sure about why it should...

Hi I am a Mech Engg student trying to study how stress is defined in quantum mechanics. I am referring to a paper where the following identity is given but i am not sure how to go about proving it The identity is \[ \left\{ {\hat A,\left[ {\nabla _i \nabla _i ,\delta \left( {{\bf{\hat r}} -...

Hi everyone, I have been reading a recent Nature paper (Stengel and Spaldin, 2006) where ab initio simulations on SrRuO_3/SrTiO_3/SrRu_O3 nanocapacitors have been performed to investigate the origin of the so-called dead layer effect in thin-film nanocapacitors. They arrive at several...

To induce the most charge on the plates of a capacitor, you should have a high-permittivity material as the dielectric . Since, for a given applied voltage, Q is directly proportional to capacitance, and capacitance is in turn proportional to the dielectric constant, capacitors which use...

In classical electrostatics, the charge resides only at the metal-dielectric interface as a delta-function. There is no charge distribution inside the metal for if this were the case , electric fields would exist inside the metal. However, in real metal electrodes the free charges do form a...

Thank you for your reply!

Hello Guys According to Classical electrostatics, when you apply a voltage across a capacitor, +Q and -Q charges are induced on a delta region at the interface of the dielectric and the metal electrode. The electric field inside the dielectric is finite and constant while the electric field in...

Hi MD...sorry i thought you were a grad student! You may have heard of Pauli's exclusion principle in the context of electrons in atoms which states that no two identical electrons can have the same quantum numbers. i.e n,l,m and the spin quantum number say 's' cannot all be the same for two...

hi ZapperZ...in hindsight, u are probably right. for some reason, i assumed OP was a grad student like me!

I am not an expert but i will say whatever i know. In the case of Bose-Einstein statistics one can have as many particles (bosons) as one likes occupying a particular energy eigenstate. Contrast this with Fermi-Dirac statistics where you can have a maximum of one fermion occupying a...

Graduate student E Kim and Prof M Chan from Penn State have published results in Nature, Science and PRL recently on the probable observation of supersolid Helium. Though these results have to be confirmed, this means that all states of matter can Bose-Einstein condense. So weird!

Have you considered using the Tersoff potential. Unlike, LJ it is not a pair potential so it should be more accurate. You can do some literature search to see if people have used tersoff like potentials for nanotubes. As far as i know, http://www.ivec.org/GULP/" is one of the MD programs that...

Hi The author calls it the two particle density matrix. The reference is Phys Rev B, Vol 71, 165104 (2005) The page number is 165104-3

Let phi(x) and phi_dagger(x) be field operators which satisfy the appropriate commutation relations. Then is there any analytic approximation for the two particle density matrix given by <phi_dagger(x)phi_dagger(x')phi(x')phi(x)> Thanks!

scarecrow thanks but can u explain in some more detail? gokul this is from a paper " quantum mechanical stress and a generalized virial theorem for clusters and solids", phys rev b vol 37 (pp 8167). the paper deals with providing a quantum mechanical framework for stress and force but...