Lorentzian Taub-NUT spacetimes: Misner string charges and the first law

Charged Taub-NUT-de Sitter spacetime in DGP braneworld and its thermodynamics*

“…where , and the Z function is given in (22). Accordingly, the resulting line element for a charged spacetime on the brane in the non-flat case can be written as…”

“…Despite obstacles related to spacetime for the NUT parameter, such as the closed timelike curve and conic singularity, recent investigations on this spacetime can still be found in literature. For example, the collisional Penrose process in Kerr-Taub-NUT spacetime is studied in [21], the thermodynamics related to NUT spacetime is explored in [22,23], and discussions on M5 branes in Taub-NUT related space are presented in [24]. For the RS-II brane scenario, the related Taub-NUT spacetime has been discussed in [25].…”

The Gravito-Electromagnetic Approximation to the Gravimagnetic Dipole and its Velocity Rotation Curve

“…In particular this asymptotically flat metric possesses a total mass M = 2m and a total angular momentum J = 2kν. Note that given the choice of natural units, all distance scales may be expressed in units of m. For sufficiently large values of k ≥ m, the system consists of two black holes connected by a spinning Misner string [19,20,21,22,23]. The quantities α − < α + and −α + < −α − correspond to the positions of the intercepts of the horizons of these black holes on the z-axisymmetric axis, while the Misner string lies along −α − < z < α − .…”

“…To describe it in simple terms, this stationary solution to the vacuum Einstein equations is sourced by two rotating black holes of identical masses m-their gravi-electric "monopole charges"-but also carrying opposite valued NUT (Newman-Unti-Tamburino) charges ±ν-their gravi-magnetic "monopole charges"-, thus connected by a Misner string singularity [19,20,21,22,23] for the space-time metric-namely nothing other than the gravimagnetic analogue of the singular magnetic flux carrying Dirac string for a Dirac monopole [24]. The analogue electromagnetic configuration is that of two dyons of identical monopole electric charges q and opposite monopole magnetic charges ±g.…”

Hidden conformal symmetry and pair production near the cosmological horizon in Kerr-Newman-Taub-NUT-de Sitter spacetime*

“…Further, the pair production can occur near the horizon of near extremal as a Schwinger effect [19][20][21][22][23] in analogy to such effect in a strong electromagnetic field. It can be shown that the violation of the Breitenlohner-Freedman bound that is associated with the massive scalar field near the horizon of a near extremal black hole leads to the conclusion that the pair production can exist.…”