718 research outputs found

### Reflecting at the Speed of Light

A perfectly reflecting accelerating boundary produces thermal emission to an
observer at $\mathscr{I}_L^+$ and a finite amount of energy to an observer at
$\mathscr{I}_R^+$ by asymptotically traveling to the speed of light without an
acceleration horizon.Comment: 4 pages, 4 figures; In memory of Kerson Huan

### Extreme Hawking Radiation

Modeling the collapse of an extreme Reissner-Nordstr\"om (ERN) black hole by
solving the corresponding moving mirror model for the trajectory that
asymptotically approaches uniform acceleration, we obtain the non-zero beta
coefficients for all times. Finite energy is emitted, the radiation spectra is
non-thermal (non-steady / not Planck), soft particles characterize the
evaporation, and particle production at ultra-late times is damped.
Entanglement entropy diverges with no Page curve turn-over, demonstrating
non-thermal information loss. The radiation obeys time-reversal symmetry.Comment: 11 pages, 12 figure

### Signatures of Energy Flux in Particle Production: A Black Hole Birth Cry and Death Gasp

It is recently argued that if the Hawking radiation process is unitary, then
a black hole's mass cannot be monotonically decreasing. We examine the time
dependent particle count and negative energy flux in the non-trivial conformal
vacuum via the moving mirror approach. A new, exactly unitary solution is
presented which emits a characteristic above-thermal positive energy burst, a
thermal plateau, and negative energy flux. It is found that the characteristic
positive energy flare and thermal plateau is observed in the particle outflow.
However, the results of time dependent particle production show no overt
indication of negative energy flux. Therefore, a black hole's birth cry is
detectable by asymptotic observers via particle count, whereas its death gasp
is not.Comment: 12 pages, 6 figure

### Slicing the Vacuum: New Accelerating Mirror Solutions of the Dynamical Casimir Effect

Radiation from accelerating mirrors in a Minkowski spacetime provides
insights into the nature of horizons, black holes, and entanglement entropy. We
introduce new, simple, symmetric and analytic moving mirror solutions and study
their particle, energy, and entropy production. This includes an asymptotically
static case with finite emission that is the black hole analog of complete
evaporation. The total energy, total entropy, total particles, and spectrum are
the same on both sides of the mirror. We also study its asymptotically
inertial, drifting analog (which gives a black hole remnant) to explore
differences in finite and infinite production.Comment: 8 pages, 10 figure

### Eternal and Evanescent Black Holes: It's All Done With Mirrors

The analogy between black hole radiation and accelerating mirror radiation
(the dynamical Casimir effect) is particularly strong for mirror trajectories
giving rise to a constant thermal flux of particles. We present new ways to
achieve such thermal plateaus, and customize their finite, semi-infinite, and
eternal presence, corresponding to forming/collapsing,
complete-evaporation/remnants, and eternal black holes. We find simple
expressions for the energy flux in terms of the mirror rapidity as a function
of proper time and null time.Comment: 13 pages, 11 figure

### Finite Energy but Infinite Entropy Production from Moving Mirrors

Accelerating mirrors provide a simple conceptual laboratory for studying
particle production and the relation between trajectory and particle, energy,
and entropy fluxes. We focus on the relation between energy and entropy,
studying some special cases with finite total energy but infinite integrated
entropy (though the entropy flux may be finite at any particular moment). We
present a new asymptotically static moving mirror trajectory with solvable beta
Bogolyubov coefficients, total energy and fully relativistic particle count.
The integrated entropy diverges despite finite global radiative particle and
energy emission. Another class of models includes exponentially accelerated
mirrors in proper time; one of its unexpected behaviors is finite energy
emission but divergent entropy. We compare mirrors exponentially accelerated in
other coordinates as well, showing their close relation and an interesting
duality property.Comment: 10 pages, 8 figures, 2 table

### Time Dependence of Particle Creation from Accelerating Mirrors

Particle production due to a quantized, massless, minimally coupled scalar
field in two-dimensional flat spacetime with an accelerating mirror is
investigated, with a focus on the time dependence of the process. We analyze
first the classes of trajectories previously investigated by Carlitz and Willey
and by Walker and Davies. We then analyze four new classes of trajectories, all
of which can be expressed analytically and for which several ancillary
properties can be derived analytically. The time dependence is investigated
through the use of wave packets for the modes of the quantized field that are
in the out vacuum state. It is shown for most of the trajectories studied that
good time resolution of the particle production process can be obtained.Comment: 21 pages, 5 figure

### Black Hole - Moving Mirror II: Particle Creation

There is an exact correspondence between the simplest solution to Einstein's
equations describing the formation of a black hole and a particular moving
mirror trajectory. In both cases the Bogolubov coefficients in 1+1 dimensions
are identical and can be computed analytically. Particle creation is
investigated by using wave packets. The entire particle creation history is
computed, incorporating the early-time non-thermal emission due to the
formation of the black hole (or the early-time acceleration of the moving
mirror) and the evolution to a Planckian spectrum.Comment: Contribution to MG14 Proceedings, 5 pages, 4 figure

### Mirror Reflections of a Black Hole

An exact correspondence between a black hole and an accelerating mirror is
demonstrated. It is shown that for a massless minimally coupled scalar field
the same Bogolubov coefficients connecting the "in" and "out" states occur for
a (1+1)D flat spacetime with a particular perfectly reflecting accelerating
boundary trajectory and a (1+1)D curved spacetime in which a null shell
collapses to form a black hole. Generalization of the latter to the (3+1)D case
is discussed. The spectral dynamics is computed in both (1+1)-dimensional
spacetimes along with the energy flux in the spacetime with a mirror. It is
shown that the approach to equilibrium is monotonic, asymmetric in terms of the
rate, and there is a specific time which characterizes the system when it is
the most out-of-equilibrium.Comment: 25 pages, 7 figure

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