solids [Archive] - Physics Forums

Minhyong Kim

Oct11-04, 03:52 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\nMost of my questions these days arise from conversations\nwith children! However, as it goes, the process of answering\nevokes the wish to understand some things better...\n\nSo where can one find an answer to the question\n\n`Why can\'t solids pass through each other\'\n\ndiscussed at an intermediate level of mathematical\nrigor? This means I don\'t need a full proof that\nsome thermodynamic limits exist and so on, but would\nappreciate a bit more than hand-waving about\nelectrostatic forces.\n\nThanks in advance.\n\nMinhyong\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>Most of my questions these days arise from conversations
with children! However, as it goes, the process of answering
evokes the wish to understand some things better...

So where can one find an answer to the question

`Why can't solids pass through each other'

discussed at an intermediate level of mathematical
rigor? This means I don't need a full proof that
some thermodynamic limits exist and so on, but would
appreciate a bit more than hand-waving about
electrostatic forces.

Thanks in advance.

Minhyong

Pieter Kuiper

Oct11-04, 01:06 PM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\nminhyongkim@yahoo.com (Minhyong Kim) wrote:\n\n> `Why can\'t solids pass through each other\'\n>\n> discussed at an intermediate level of mathematical\n> rigor? This means I don\'t need a full proof that\n> some thermodynamic limits exist and so on, but would\n> appreciate a bit more than hand-waving about\n> electrostatic forces.\n\nIt is not so much electrostatics as quantum mechanics.\n\nCondensed systems are (almost) incompressible because of the Pauli\nprinciple for electrons. The compressibility of alkali metals is of the\nsame order of magnitude as theoretical expression for the\ncompressibility of a free electron Fermi gas with the same particle\ndensity.\n\n--\n"Electrons damage the brain," said Farish. (Donna Tartt)\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>minhyongkim@yahoo.com (Minhyong Kim) wrote:

> `Why can't solids pass through each other'
>
> discussed at an intermediate level of mathematical
> rigor? This means I don't need a full proof that
> some thermodynamic limits exist and so on, but would
> appreciate a bit more than hand-waving about
> electrostatic forces.

It is not so much electrostatics as quantum mechanics.

Condensed systems are (almost) incompressible because of the Pauli
principle for electrons. The compressibility of alkali metals is of the
same order of magnitude as theoretical expression for the
compressibility of a free electron Fermi gas with the same particle
density.

--
"Electrons damage the brain," said Farish. (Donna Tartt)