| 227 |
|
momentum variables. Consider a dynamic system of $f$ particles in a |
| 228 |
|
cartesian space, where each of the $6f$ coordinates and momenta is |
| 229 |
|
assigned to one of $6f$ mutually orthogonal axes, the phase space of |
| 230 |
< |
this system is a $6f$ dimensional space. A point, $x = (q_1 , \ldots |
| 231 |
< |
,q_f ,p_1 , \ldots ,p_f )$, with a unique set of values of $6f$ |
| 232 |
< |
coordinates and momenta is a phase space vector. |
| 233 |
< |
|
| 230 |
> |
this system is a $6f$ dimensional space. A point, $x = (\rightarrow |
| 231 |
> |
q_1 , \ldots ,\rightarrow q_f ,\rightarrow p_1 , \ldots ,\rightarrow |
| 232 |
> |
p_f )$, with a unique set of values of $6f$ coordinates and momenta |
| 233 |
> |
is a phase space vector. |
| 234 |
|
%%%fix me |
| 235 |
< |
A microscopic state or microstate of a classical system is |
| 236 |
< |
specification of the complete phase space vector of a system at any |
| 237 |
< |
instant in time. An ensemble is defined as a collection of systems |
| 238 |
< |
sharing one or more macroscopic characteristics but each being in a |
| 239 |
< |
unique microstate. The complete ensemble is specified by giving all |
| 240 |
< |
systems or microstates consistent with the common macroscopic |
| 241 |
< |
characteristics of the ensemble. Although the state of each |
| 242 |
< |
individual system in the ensemble could be precisely described at |
| 243 |
< |
any instance in time by a suitable phase space vector, when using |
| 244 |
< |
ensembles for statistical purposes, there is no need to maintain |
| 245 |
< |
distinctions between individual systems, since the numbers of |
| 246 |
< |
systems at any time in the different states which correspond to |
| 247 |
< |
different regions of the phase space are more interesting. Moreover, |
| 248 |
< |
in the point of view of statistical mechanics, one would prefer to |
| 249 |
< |
use ensembles containing a large enough population of separate |
| 250 |
< |
members so that the numbers of systems in such different states can |
| 251 |
< |
be regarded as changing continuously as we traverse different |
| 252 |
< |
regions of the phase space. The condition of an ensemble at any time |
| 235 |
> |
|
| 236 |
> |
In statistical mechanics, the condition of an ensemble at any time |
| 237 |
|
can be regarded as appropriately specified by the density $\rho$ |
| 238 |
|
with which representative points are distributed over the phase |
| 239 |
|
space. The density distribution for an ensemble with $f$ degrees of |
| 1241 |
|
\] |
| 1242 |
|
|
| 1243 |
|
Unfortunately, this constraint manifold is not the cotangent bundle |
| 1244 |
< |
$T_{\star}SO(3)$. However, it turns out that under symplectic |
| 1244 |
> |
$T^* SO(3)$ which can be consider as a symplectic manifold on Lie |
| 1245 |
> |
rotation group $SO(3)$. However, it turns out that under symplectic |
| 1246 |
|
transformation, the cotangent space and the phase space are |
| 1247 |
|
diffeomorphic. By introducing |
| 1248 |
|
\[ |
| 1280 |
|
introduced to rewrite the equations of motion, |
| 1281 |
|
\begin{equation} |
| 1282 |
|
\begin{array}{l} |
| 1283 |
< |
\mathop \Pi \limits^ \bullet = J^{ - 1} \Pi ^T \Pi + Q^T \sum\limits_i {F_i (q,Q)X_i^T } - \Lambda \\ |
| 1284 |
< |
\mathop Q\limits^{{\rm{ }} \bullet } = Q\Pi {\rm{ }}J^{ - 1} \\ |
| 1283 |
> |
\dot \Pi = J^{ - 1} \Pi ^T \Pi + Q^T \sum\limits_i {F_i (q,Q)X_i^T } - \Lambda \\ |
| 1284 |
> |
\dot Q = Q\Pi {\rm{ }}J^{ - 1} \\ |
| 1285 |
|
\end{array} |
| 1286 |
|
\label{introEqaution:RBMotionPI} |
| 1287 |
|
\end{equation} |
| 1311 |
|
\] |
| 1312 |
|
Using \ref{introEqaution:RBMotionPI}, one can construct a skew |
| 1313 |
|
matrix, |
| 1314 |
< |
\begin{equation} |
| 1315 |
< |
(\mathop \Pi \limits^ \bullet - \mathop \Pi \limits^ {\bullet ^T} |
| 1316 |
< |
){\rm{ }} = {\rm{ }}(\Pi - \Pi ^T ){\rm{ }}(J^{ - 1} \Pi + \Pi J^{ |
| 1317 |
< |
- 1} ) + \sum\limits_i {[Q^T F_i (r,Q)X_i^T - X_i F_i (r,Q)^T Q]} - |
| 1318 |
< |
(\Lambda - \Lambda ^T ) . \label{introEquation:skewMatrixPI} |
| 1319 |
< |
\end{equation} |
| 1314 |
> |
|
| 1315 |
> |
\begin{eqnarry*} |
| 1316 |
> |
(\dot \Pi - \dot \Pi ^T ){\rm{ }} = {\rm{ }}(\Pi - \Pi ^T ){\rm{ |
| 1317 |
> |
}}(J^{ - 1} \Pi + \Pi J^{ - 1} ) + \sum\limits_i {[Q^T F_i |
| 1318 |
> |
(r,Q)X_i^T - X_i F_i (r,Q)^T Q]} - (\Lambda - \Lambda ^T ). |
| 1319 |
> |
\label{introEquation:skewMatrixPI} |
| 1320 |
> |
\end{eqnarray*} |
| 1321 |
> |
|
| 1322 |
|
Since $\Lambda$ is symmetric, the last term of Equation |
| 1323 |
|
\ref{introEquation:skewMatrixPI} is zero, which implies the Lagrange |
| 1324 |
|
multiplier $\Lambda$ is absent from the equations of motion. This |
