## Nuclear, Particle, Astroparticle and Cosmology (NUPAC) Seminars

### Surface Tension and Negative Pressure Interior of a Non-Singular `Black Hole'

#### Presented by Emil Mottola (LANL)

The constant density interior Schwarzschild solution for a static, spherically symmetric collapsed star has a divergent pressure when its radius is less than 9/8 the Schwarzschild radius. However, this divergence is integrable, and induces a non-isotropic transverse stress with a finite redshifted surface tension on a spherical surface of a certain finite radius inside the star. Within this finite radius the interior Schwarzschild solution exhibits negative pressure. When the the star is compacted to its Schwarzschild radius, the interior surface is localized at the Schwarzschild radius itself, and the solution has constant negative pressure everywhere in its interior, thus describing a gravitational

condensate star, a fully collapsed non-singular state already inherent in and predicted by classical General Relativity. Since there is no event horizon, the Schwarzschild time of such a non-singular gravitational condensate star is a global time, fully consistent with unitary time evolution in quantum theory. The dark energy interior acts as a defocusing lens for light passing through the condensate, leading to imaging characteristics distinguishable from a classical black hole. A further observational test of gravitational condensate stars with a physical surface vs. black holes is the discrete surface modes of oscillation, and gravitational 'echoes' which should be detectable by their gravitational wave signatures.

**2:00 pm, Tuesday, April 25, 2017
Room 190, Physics & Astronomy
Northeast corner of Lomas and Yale, Albuquerque, New Mexico**

Individuals with disabilities who need an auxiliary aid or service to attend or participate in P&A events should contact Sandra Ortiz (phone: 505-277-5900, email: sportiz@unm.edu) well in advance to ensure your needs are accomodated. Event handouts can be provided in alternative accessible formats upon request. Please contact Mrs. Ortiz if you need written information in an alternative format.

*A schedule of talks within the Department of Physics and Astronomy is available on the P&A web site at http://physics.unm.edu/pandaweb/events/index.php*