Mesonic screening correlators in an external imaginary electric field at finite temperature

Abstract

External electromagnetic fields provide a useful probe of QCD matter, but real electric fields are hindered by the sign problem, motivating studies with imaginary electric fields. We investigate mesonic screening correlators in lattice QCD at finite temperature in the presence of such a background using staggered fermions. At low temperature, scalar screening masses increase with the field strength, while pseudo-scalar masses remain largely unchanged, and charge-asymmetric channels show additional structure. At high temperature, the correlators exhibit clear spatial oscillations with frequencies set by the quark electric charges. These results demonstrate nontrivial modifications of screening properties induced by external electric fields.

Figures (16)

• Figure 1: $c_q$ as functions of $E_x$ at $\beta=5.3$ (left panel) and $\beta=5.8$ (right panel).
• Figure 2: The oscillations of $c_u(x)$ along $x$-axis and the fitted results according to Eq. (\ref{['eq.3.2']}) at $\beta=5.8$.
• Figure 3: Same as Fig. \ref{['fig:chiralfit580u']} but for $c_d(x)$.
• Figure 4: Same as Fig. \ref{['fig:chiralfit580u']} but for $c^4_u(x)$. Note that for the case of $c^4_u$ and $k=6$, $B^4_u$ cannot be fitted. Just for the sake of the schematic, we took an arbitrary $B^4_u$ in this special case. We use a $B^4_u=0.005$ which is at the same order of $B^4_u$ in other cases.
• Figure 5: Same as Fig. \ref{['fig:chiralfit580u']} but for $c^4_d(x)$.