Energy momentum tensor, and theD-term ofQ-balls

Abstract

We study the energy-momentum tensor of stable, meta-stable and unstable Q-balls in scalar field theories with U(1) symmetry. We calculate properties such as charge, mass, mean square radii and the constant d1 ("D-term") as functions of the phase space angular velocity ω. We discuss the limits when ω approaches the boundaries of the region in which solutions exist, and derive analytical results for the quantities in these limits. The central result of this work is the rigorous proof that d1 is strictly negative for all finite energy solutions in the Q-ball system. We also show that for Q-balls stability is a sufficient, but not necessary, condition for d1 to be negative.

Mechanical properties of particles

“…Numerical studies of the Q-balls (see discussion of EMT for Q-balls in [20,21]) shows that the inequalities (27) as well as the bound (32) are always satisfied, but the conjectured inequalities (31) are violated even for the stable Q-balls. This violation happens only in the small region close to the centre of the soliton.…”

Gravitational form factors and nucleon spin structure

“…C has definite (positive) sign in all known cases, including hadrons (see [42], which also discusses general stability arguments), photons [45], and Q-balls [46,47]. It is interesting to compare [48] this decomposition to the vacuum matrix element when one has the well-known cosmological constant:…”

Scattering of the φ8 kinks with power-law asymptotics

“…Many interesting and important results have been obtained in the (1+1)dimensional models with polynomial potentials: ϕ 4 , ϕ 6 , ϕ 8 , and so on [55][56][57][58][59][60][61][63][64][65][66][67][68][69][70]]. An impressive progress has been achieved in the studies of Q-balls [71][72][73][74][75][76][77][78], embedded topological defects, e.g., a skyrmion on a domain wall [79,80], a Q-lump on a domain wall [81], fermionic states on a domain wall [82][83][84][85][86][87], etc. [88][89][90][91][92][93].…”