on the use of the traceless stress tensor (TST). It is shown that it naturally leads to the appearance of a modiﬁed viscosity given by C. =3/ tr.˝/ where is the shear-viscosity coefﬁcient, the relaxation time and tr(˝) the trace of the extra stress tensor. This modiﬁed …

Electromagnetism II, Lecture Notes 9 symmetric tensor, because it is just a number. (I am using. S. for symmetric tensors, while reserving. C. for traceless symmetric tensors.) It takes 3 numbers to specify. S (1) i, since the 3 values. S (1) (1) (1) 1, S (2) 2,and. S. 3. can each be speciﬁed independently. For. S. ij, however, weseetheconstraintsofsymmetry: S (2) hastoequal (2 Cosmological Dynamics - E. Bertschinger We have introduced two 3-scalar fields (x, ) and (x, ), one 3-vector field w(x, ) = w i e i, and one symmetric, traceless second-rank 3-tensor field h(x, ) = h ij e i e j.No generality is lost by making h ij traceless since any trace part can be put into .The factors of 2 and signs have been chosen to simplify later expressions. Quantum Field Theory: Is there any physical interpretation

## Casimir energy of the CFT on a toroidal geometry. Finally, we present a discussion of our results in section 4. While this paper was in preparation, ref. [14] appeared which discusses calculating the CFT stress-energy using techniques similar to those in section 2.2. 2 Stress-Energy Tensor

Now, this theory is scale-invariant (due to tracelessness of the energy-momentum tensor), thus intuitively I expect that its excitations should be massless and therefore travel at the speed of light. However, I cannot find a way to prove it formally. Cosmological Dynamics - E. Bertschinger Stress-energy tensor. The Einstein field eqs. (4.7) show that the stress-energy tensor provides the source for the metric variables. For a perfect fluid the stress-energy tensor takes the well-known form Note that the traceless shear stress j i may be decomposed as in eqs. (4.13) and (4.14) into scalar, vector, and tensor parts. Similarly, ON THE GRAVITOELECTROMAGNETIC STRESS-ENERGY …

### The Stress Tensor of the Electromagnetic Field

Construction of the stress-energy tensor: second approach 219 Figure 77: A designated drop of liquid (think of a drop of ink dripped into a glass of water) shown at times t and t+dt.Every point in the evolved drop originated as a point in the initial drop. Not shown is the surrounding ﬂuid. Electromagnetic field correlators, Maxwell stress tensor The local behavior of the Maxwell tensor, or of the relativistic symmetrical stress-energy tensor, is extremely important because as shown by, for example, Deutsch and Candelas [9] with the help of Green functions techniques, as we approach the boundaries we find strong divergencies that cannot be simply removed by usual renormalization procedures. Regularization of the Stress Energy Tensor for Vector and