The basic imports and the variables we'll be using:


In [1]:
from __future__ import division
import sympy
from sympy import *
from sympy import Rational as frac
import simpletensors
from simpletensors import Vector, TensorProduct, SymmetricTensorProduct, Tensor
init_printing()


var('vartheta, varphi')
var('nu, m, delta, c, t')

# These are related scalar functions of time
var('r, v, Omega', cls=Function)
r = r(t)
v = v(t)
Omega = Omega(t)

# These get redefined momentarily, but have to exist first
var('nHat, lambdaHat, ellHat', cls=Function)
# And now we define them as vector functions of time
nHat = Vector('nHat', r'\hat{n}', [cos(Omega*t),sin(Omega*t),0,])(t)
lambdaHat = Vector('lambdaHat', r'\hat{\lambda}', [-sin(Omega*t),cos(Omega*t),0,])(t)
ellHat = Vector('ellHat', r'\hat{\ell}', [0,0,1,])(t)

# These are the spin functions -- first, the individual components as regular sympy.Function objects; then the vectors themselves
var('S_n, S_lambda, S_ell', cls=Function)
var('Sigma_n, Sigma_lambda, Sigma_ell', cls=Function)
SigmaVec = Vector('SigmaVec', r'\vec{\Sigma}', [Sigma_n(t), Sigma_lambda(t), Sigma_ell(t)])(t)
SVec = Vector('S', r'\vec{S}', [S_n(t), S_lambda(t), S_ell(t)])(t)

Examples and tests


In [3]:
nHat


Out[3]:
$$\hat{n}$$

In [4]:
diff(nHat, t)


Out[4]:
$$\partial_t \hat{n}$$

In [5]:
diff(lambdaHat, t)


Out[5]:
$$\partial_t \hat{\lambda}$$

In [6]:
diff(lambdaHat, t).components


Out[6]:
$$\begin{bmatrix}- \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \cos{\left (t \Omega{\left (t \right )} \right )}, & - \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \sin{\left (t \Omega{\left (t \right )} \right )}, & 0\end{bmatrix}$$

In [7]:
diff(lambdaHat, t).subs(t,0).components


Out[7]:
$$\begin{bmatrix}- \Omega{\left (0 \right )}, & 0, & 0\end{bmatrix}$$

In [8]:
diff(lambdaHat, t, 2).components


Out[8]:
$$\begin{bmatrix}\left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right)^{2} \sin{\left (t \Omega{\left (t \right )} \right )} - \left(t \frac{d^{2}}{d t^{2}} \Omega{\left (t \right )} + 2 \frac{d}{d t} \Omega{\left (t \right )}\right) \cos{\left (t \Omega{\left (t \right )} \right )}, & - \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right)^{2} \cos{\left (t \Omega{\left (t \right )} \right )} - \left(t \frac{d^{2}}{d t^{2}} \Omega{\left (t \right )} + 2 \frac{d}{d t} \Omega{\left (t \right )}\right) \sin{\left (t \Omega{\left (t \right )} \right )}, & 0\end{bmatrix}$$

In [9]:
diff(lambdaHat, t, 2).subs(t,0).components


Out[9]:
$$\begin{bmatrix}- 2 \left. \frac{d}{d t} \Omega{\left (t \right )} \right|_{\substack{ t=0 }}, & - \Omega^{2}{\left (0 \right )}, & 0\end{bmatrix}$$

In [10]:
diff(ellHat, t)


Out[10]:
$$0$$

In [11]:
diff(nHat, t, 2)


Out[11]:
$$\partial_t^{2} \hat{n}$$

In [12]:
diff(nHat,t, 3)


Out[12]:
$$\partial_t^{3} \hat{n}$$

In [13]:
diff(nHat,t, 4)


Out[13]:
$$\partial_t^{4} \hat{n}$$

In [14]:
diff(SigmaVec,t, 0)


Out[14]:
$$\vec{\Sigma}$$

In [15]:
SigmaVec.fdiff()


Out[15]:
$$\partial_t \vec{\Sigma}$$

In [16]:
diff(SigmaVec,t, 1)


Out[16]:
$$\partial_t \vec{\Sigma}$$

In [17]:
diff(SigmaVec,t, 2)


Out[17]:
$$\partial_t^{2} \vec{\Sigma}$$

In [18]:
diff(SigmaVec,t, 2) | nHat


Out[18]:
$$\sin{\left (t \Omega{\left (t \right )} \right )} \frac{d^{2}}{d t^{2}} \Sigma_{\lambda}{\left (t \right )} + \cos{\left (t \Omega{\left (t \right )} \right )} \frac{d^{2}}{d t^{2}} \Sigma_{n}{\left (t \right )}$$

In [19]:
T1 = TensorProduct(SigmaVec, SigmaVec, ellHat, coefficient=1)
T2 = TensorProduct(SigmaVec, nHat, lambdaHat, coefficient=1)
tmp = Tensor(T1,T2)
display(T1, T2, tmp)


$$\left(\vec{\Sigma} \otimes \vec{\Sigma} \otimes \hat{\ell}\right)$$
$$\left(\vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda}\right)$$
$$\begin{align*}&\left[ \left(\vec{\Sigma} \otimes \vec{\Sigma} \otimes \hat{\ell}\right) \right. \nonumber \\&\quad \left. + \left(\vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda}\right) \right]\end{align*}$$

In [20]:
diff(tmp, t, 1)


Out[20]:
$$\begin{align*}&\left[ \left(\partial_t \vec{\Sigma} \otimes \vec{\Sigma} \otimes \hat{\ell}\right) \right. \nonumber \\&\quad \left. + \left(\vec{\Sigma} \otimes \partial_t \vec{\Sigma} \otimes \hat{\ell}\right) \right. \nonumber \\&\quad \left. + \left(\partial_t \vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda}\right) \right. \nonumber \\&\quad \left. + \left(\vec{\Sigma} \otimes \partial_t \hat{n} \otimes \hat{\lambda}\right) \right. \nonumber \\&\quad \left. + \left(\vec{\Sigma} \otimes \hat{n} \otimes \partial_t \hat{\lambda}\right) \right]\end{align*}$$

In [21]:
T1+T2


Out[21]:
$$\begin{align*}&\left[ \left(\vec{\Sigma} \otimes \vec{\Sigma} \otimes \hat{\ell}\right) \right. \nonumber \\&\quad \left. + \left(\vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda}\right) \right]\end{align*}$$

In [22]:
T2*ellHat


Out[22]:
$$\left(\vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda} \otimes \hat{\ell}\right)$$

In [23]:
ellHat*T2


Out[23]:
$$\left(\hat{\ell} \otimes \vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda}\right)$$

In [24]:
T1.trace(0,1)


Out[24]:
$$\left\{ \left[ \Sigma_{\ell}^{2}{\left (t \right )} + \Sigma_{\lambda}^{2}{\left (t \right )} + \Sigma_{n}^{2}{\left (t \right )} \right]\, \hat{\ell} \right\}$$

In [25]:
T2*ellHat


Out[25]:
$$\left(\vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda} \otimes \hat{\ell}\right)$$

In [26]:
for k in range(1,4):
    display((T2*ellHat).trace(0,k))


$$\left\{ \left[ \Sigma_{\lambda}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \Sigma_{n}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} \right]\, \hat{\lambda} \otimes \hat{\ell} \right\}$$
$$\left\{ \left[ \Sigma_{\lambda}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} - \Sigma_{n}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} \right]\, \hat{n} \otimes \hat{\ell} \right\}$$
$$\left\{ \left[ \Sigma_{\ell}{\left (t \right )} \right]\, \hat{n} \otimes \hat{\lambda} \right\}$$

In [27]:
for k in range(1,4):
    display((T2*ellHat).trace(0,k).subs(t,0))


$$\left\{ \left[ \Sigma_{\lambda}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \Sigma_{n}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} \right]\, \hat{\lambda} \otimes \hat{\ell} \right\}$$
$$\left\{ \left[ \Sigma_{\lambda}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} - \Sigma_{n}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} \right]\, \hat{n} \otimes \hat{\ell} \right\}$$
$$\left\{ \left[ \Sigma_{\ell}{\left (t \right )} \right]\, \hat{n} \otimes \hat{\lambda} \right\}$$

In [28]:
T1.trace(0,1) * T2


Out[28]:
$$\left\{ \left[ \Sigma_{\ell}^{2}{\left (t \right )} + \Sigma_{\lambda}^{2}{\left (t \right )} + \Sigma_{n}^{2}{\left (t \right )} \right]\, \hat{\ell} \otimes \vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda} \right\}$$

Sympy can be a little tricky because it caches things, which means that the first implementation of this code silently changed tensors in place, without meaning to. Let's just check that our variables haven't changed:


In [29]:
display(T1, T2)


$$\left(\vec{\Sigma} \otimes \vec{\Sigma} \otimes \hat{\ell}\right)$$
$$\left(\vec{\Sigma} \otimes \hat{n} \otimes \hat{\lambda}\right)$$

In [30]:
T3 = SymmetricTensorProduct(SigmaVec, SigmaVec, ellHat, coefficient=1)
display(T3)
T3.trace(0,1)


$$\left(\vec{\Sigma} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell}\right)$$
Out[30]:
$$\begin{align*}&\left\{ \left\{ \left[ \frac{1}{3} \Sigma_{\ell}^{2}{\left (t \right )} + \frac{1}{3} \Sigma_{\lambda}^{2}{\left (t \right )} + \frac{1}{3} \Sigma_{n}^{2}{\left (t \right )} \right]\, \hat{\ell} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{2}{3} \Sigma_{\ell}{\left (t \right )} \right]\, \vec{\Sigma} \right\} \right\}\end{align*}$$

In [31]:
diff(T3, t, 1)


Out[31]:
$$\begin{align*}&\left\{ \left[ \left(2\right)\, \partial_t \vec{\Sigma} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \right] \right\}\end{align*}$$

In [32]:
T3.symmetric


Out[32]:
True

In [33]:
T3*ellHat


Out[33]:
$$\left(\vec{\Sigma} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \otimes_{\mathrm{s}} \hat{\ell}\right)$$

In [34]:
ellHat*T3


Out[34]:
$$\left(\hat{\ell} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell}\right)$$

In [35]:
T1+T3


Out[35]:
$$\begin{align*}&\left[ \left(\vec{\Sigma} \otimes \vec{\Sigma} \otimes \hat{\ell}\right) \right. \nonumber \\&\quad \left. + \left(\vec{\Sigma} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell}\right) \right]\end{align*}$$

In [6]:
T1 = SymmetricTensorProduct(SigmaVec, SigmaVec, ellHat, nHat, coefficient=1)
display(T1)
display(T1.trace())


$$\left(\vec{\Sigma} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \otimes_{\mathrm{s}} \hat{n}\right)$$
$$\begin{align*}&\left( \left\{ \left[ \frac{1}{12} \Sigma_{\ell}^{2}{\left (t \right )} + \frac{1}{12} \Sigma_{\lambda}^{2}{\left (t \right )} + \frac{1}{12} \Sigma_{n}^{2}{\left (t \right )} \right]\, \hat{\ell} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\lambda}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \frac{1}{6} \Sigma_{n}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \right\} \right)\end{align*}$$

In [37]:
T1*T2


Out[37]:
$$\left(\vec{\Sigma} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \otimes_{\mathrm{s}} \hat{n} \otimes_{\mathrm{s}} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{n} \otimes_{\mathrm{s}} \hat{\lambda}\right)$$

In [38]:
type(_)


Out[38]:
simpletensors.TensorProductFunction_73

In [39]:
import simpletensors
isinstance(__, simpletensors.TensorProductFunction)


Out[39]:
True

In [40]:
SymmetricTensorProduct(nHat, nHat, nHat).trace()


Out[40]:
$$\begin{align*}&\left[ \left(\hat{n}\right) \right]\end{align*}$$

In [7]:
diff(T1.trace(), t, 1)


Out[7]:
$$\begin{align*}&\left( \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (t \right )} \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} + \frac{1}{6} \Sigma_{\lambda}{\left (t \right )} \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} + \frac{1}{6} \Sigma_{n}{\left (t \right )} \frac{d}{d t} \Sigma_{n}{\left (t \right )} \right]\, \hat{\ell} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{12} \Sigma_{\ell}^{2}{\left (t \right )} + \frac{1}{12} \Sigma_{\lambda}^{2}{\left (t \right )} + \frac{1}{12} \Sigma_{n}^{2}{\left (t \right )} \right]\, \hat{\ell} \otimes_{\mathrm{s}} \partial_t \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (t \right )} \right]\, \partial_t \vec{\Sigma} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \partial_t \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \Sigma_{\lambda}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} - \frac{1}{6} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \Sigma_{n}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \frac{1}{6} \sin{\left (t \Omega{\left (t \right )} \right )} \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} + \frac{1}{6} \cos{\left (t \Omega{\left (t \right )} \right )} \frac{d}{d t} \Sigma_{n}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\lambda}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \frac{1}{6} \Sigma_{n}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} \right]\, \partial_t \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \right\} \right)\end{align*}$$

In [8]:
diff(T1.trace(), t, 2)


Out[8]:
$$\begin{align*}&\left( \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (t \right )} \frac{d^{2}}{d t^{2}} \Sigma_{\ell}{\left (t \right )} + \frac{1}{6} \Sigma_{\lambda}{\left (t \right )} \frac{d^{2}}{d t^{2}} \Sigma_{\lambda}{\left (t \right )} + \frac{1}{6} \Sigma_{n}{\left (t \right )} \frac{d^{2}}{d t^{2}} \Sigma_{n}{\left (t \right )} + \frac{1}{6} \left(\frac{d}{d t} \Sigma_{\ell}{\left (t \right )}\right)^{2} + \frac{1}{6} \left(\frac{d}{d t} \Sigma_{\lambda}{\left (t \right )}\right)^{2} + \frac{1}{6} \left(\frac{d}{d t} \Sigma_{n}{\left (t \right )}\right)^{2} \right]\, \hat{\ell} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \Sigma_{\ell}{\left (t \right )} \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} + \frac{1}{3} \Sigma_{\lambda}{\left (t \right )} \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} + \frac{1}{3} \Sigma_{n}{\left (t \right )} \frac{d}{d t} \Sigma_{n}{\left (t \right )} \right]\, \hat{\ell} \otimes_{\mathrm{s}} \partial_t \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{12} \Sigma_{\ell}^{2}{\left (t \right )} + \frac{1}{12} \Sigma_{\lambda}^{2}{\left (t \right )} + \frac{1}{12} \Sigma_{n}^{2}{\left (t \right )} \right]\, \hat{\ell} \otimes_{\mathrm{s}} \partial_t^{2} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \frac{d^{2}}{d t^{2}} \Sigma_{\ell}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} \right]\, \partial_t \vec{\Sigma} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \partial_t \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (t \right )} \right]\, \partial_t^{2} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \Sigma_{\ell}{\left (t \right )} \right]\, \partial_t \vec{\Sigma} \otimes_{\mathrm{s}} \partial_t \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \partial_t^{2} \hat{n} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ - \frac{1}{6} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right)^{2} \Sigma_{\lambda}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} - \frac{1}{6} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right)^{2} \Sigma_{n}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} - \frac{1}{3} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \sin{\left (t \Omega{\left (t \right )} \right )} \frac{d}{d t} \Sigma_{n}{\left (t \right )} + \frac{1}{3} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \cos{\left (t \Omega{\left (t \right )} \right )} \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} + \frac{1}{6} \left(t \frac{d^{2}}{d t^{2}} \Omega{\left (t \right )} + 2 \frac{d}{d t} \Omega{\left (t \right )}\right) \Sigma_{\lambda}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} - \frac{1}{6} \left(t \frac{d^{2}}{d t^{2}} \Omega{\left (t \right )} + 2 \frac{d}{d t} \Omega{\left (t \right )}\right) \Sigma_{n}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \frac{1}{6} \sin{\left (t \Omega{\left (t \right )} \right )} \frac{d^{2}}{d t^{2}} \Sigma_{\lambda}{\left (t \right )} + \frac{1}{6} \cos{\left (t \Omega{\left (t \right )} \right )} \frac{d^{2}}{d t^{2}} \Sigma_{n}{\left (t \right )} \right]\, \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \Sigma_{\lambda}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} - \frac{1}{3} \left(t \frac{d}{d t} \Omega{\left (t \right )} + \Omega{\left (t \right )}\right) \Sigma_{n}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \frac{1}{3} \sin{\left (t \Omega{\left (t \right )} \right )} \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} + \frac{1}{3} \cos{\left (t \Omega{\left (t \right )} \right )} \frac{d}{d t} \Sigma_{n}{\left (t \right )} \right]\, \partial_t \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\lambda}{\left (t \right )} \sin{\left (t \Omega{\left (t \right )} \right )} + \frac{1}{6} \Sigma_{n}{\left (t \right )} \cos{\left (t \Omega{\left (t \right )} \right )} \right]\, \partial_t^{2} \vec{\Sigma} \otimes_{\mathrm{s}} \hat{\ell} \right\} \right)\end{align*}$$

In [9]:
diff(T1.trace(), t, 2).subs(t,0)


Out[9]:
$$\begin{align*}&\left( \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (0 \right )} \left. \frac{d^{2}}{d t^{2}} \Sigma_{\ell}{\left (t \right )} \right|_{\substack{ t=0 }} + \frac{1}{6} \Sigma_{\lambda}{\left (0 \right )} \left. \frac{d^{2}}{d t^{2}} \Sigma_{\lambda}{\left (t \right )} \right|_{\substack{ t=0 }} + \frac{1}{6} \Sigma_{n}{\left (0 \right )} \left. \frac{d^{2}}{d t^{2}} \Sigma_{n}{\left (t \right )} \right|_{\substack{ t=0 }} + \frac{1}{6} \left(\left. \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} \right|_{\substack{ t=0 }}\right)^{2} + \frac{1}{6} \left(\left. \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} \right|_{\substack{ t=0 }}\right)^{2} + \frac{1}{6} \left(\left. \frac{d}{d t} \Sigma_{n}{\left (t \right )} \right|_{\substack{ t=0 }}\right)^{2} \right]\, \left.\hat{\ell}\right|_{t=0} \otimes_{\mathrm{s}} \left.\hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \Sigma_{\ell}{\left (0 \right )} \left. \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} \right|_{\substack{ t=0 }} + \frac{1}{3} \Sigma_{\lambda}{\left (0 \right )} \left. \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} \right|_{\substack{ t=0 }} + \frac{1}{3} \Sigma_{n}{\left (0 \right )} \left. \frac{d}{d t} \Sigma_{n}{\left (t \right )} \right|_{\substack{ t=0 }} \right]\, \left.\hat{\ell}\right|_{t=0} \otimes_{\mathrm{s}} \left.\partial_t \hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{12} \Sigma_{\ell}^{2}{\left (0 \right )} + \frac{1}{12} \Sigma_{\lambda}^{2}{\left (0 \right )} + \frac{1}{12} \Sigma_{n}^{2}{\left (0 \right )} \right]\, \left.\hat{\ell}\right|_{t=0} \otimes_{\mathrm{s}} \left.\partial_t^{2} \hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \left. \frac{d^{2}}{d t^{2}} \Sigma_{\ell}{\left (t \right )} \right|_{\substack{ t=0 }} \right]\, \left.\vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \left. \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} \right|_{\substack{ t=0 }} \right]\, \left.\partial_t \vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \left. \frac{d}{d t} \Sigma_{\ell}{\left (t \right )} \right|_{\substack{ t=0 }} \right]\, \left.\vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\partial_t \hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (0 \right )} \right]\, \left.\partial_t^{2} \vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \Sigma_{\ell}{\left (0 \right )} \right]\, \left.\partial_t \vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\partial_t \hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{\ell}{\left (0 \right )} \right]\, \left.\vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\partial_t^{2} \hat{n}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ - \frac{1}{6} \Omega^{2}{\left (0 \right )} \Sigma_{n}{\left (0 \right )} + \frac{1}{3} \Omega{\left (0 \right )} \left. \frac{d}{d t} \Sigma_{\lambda}{\left (t \right )} \right|_{\substack{ t=0 }} + \frac{1}{3} \Sigma_{\lambda}{\left (0 \right )} \left. \frac{d}{d t} \Omega{\left (t \right )} \right|_{\substack{ t=0 }} + \frac{1}{6} \left. \frac{d^{2}}{d t^{2}} \Sigma_{n}{\left (t \right )} \right|_{\substack{ t=0 }} \right]\, \left.\vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\hat{\ell}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{3} \Omega{\left (0 \right )} \Sigma_{\lambda}{\left (0 \right )} + \frac{1}{3} \left. \frac{d}{d t} \Sigma_{n}{\left (t \right )} \right|_{\substack{ t=0 }} \right]\, \left.\partial_t \vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\hat{\ell}\right|_{t=0} \right\} \right. \nonumber \\&\quad \left. + \left\{ \left[ \frac{1}{6} \Sigma_{n}{\left (0 \right )} \right]\, \left.\partial_t^{2} \vec{\Sigma}\right|_{t=0} \otimes_{\mathrm{s}} \left.\hat{\ell}\right|_{t=0} \right\} \right)\end{align*}$$

In [ ]: