Giant Tortoise Coordinate
The giant tortoise coordinate is a moving mirror inspired generalization of the Regge-Wheeler counterpart that demonstrates a unitary evaporating black hole emitting a total finite energy.
gr-qc↗
arXiv subjects
Michael R. R. Good
Publications and source records attributed to Michael R. R. Good.
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.
gr-qc↗
On a Uniformly Accelerated Point Charge moving along a Cusp
A uniformly accelerated point charge which moves neither in a straight line nor in a circle, but in a cusp, is investigated. We find the angular distribution of the Larmor radiation, the constant power, and the intensity in the maximal direction. It is found that the intensity of uniformly accelerated cusp motion scales like non-uniformly accelerated synchrotron radiation. We confirm the exact vacuum excitation spectra of quantized field detectors on the world line.
physics.class-ph↗
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.
gr-qc↗
On Horizonless Temperature with an Accelerating Mirror
A new solution of a unitary moving mirror is found to produce finite energy and emit thermal radiation despite the absence of an acceleration horizon. In the limit that the mirror approaches the speed of light, the model corresponds to a black hole formed from the collapse of a null shell. For speeds less than light, the black hole correspondence, if it exists, is that of a remnant.
gr-qc↗
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.
gr-qc↗
Geometric creation of quantum vorticity
We consider superfluidity and quantum vorticity in rotating spacetimes. The system is described by a complex scalar satisfying a nonlinear Klein-Gordon equation. Rotation terms are identified and found to lead to the transfer of angular momentum of the spacetime to the scalar field. The scalar field responds by rotating, physically behaving as a superfluid, through the creation of quantized vortices. We demonstrate the vortex nucleation through numerical simulation.
gr-qc↗
Reflections on a Black Mirror
A black mirror is an accelerated boundary that produces particles in an exact correspondence to an evaporating black hole. We investigate the spectral dynamics of the particle creation during the formation process.
gr-qc↗
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.
gr-qc↗
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.
gr-qc↗
Black Hole - Moving Mirror I: An Exact Correspondence
An exact correspondence is shown between a new moving mirror trajectory in (1+1)D and a spacetime in (1+1)D in which a black hole forms from the collapse of a null shell. It is shown that the Bogolubov coefficients between the "in" and "out" states are identical and the exact Bogolubov coefficients are displayed. Generalization to the (3+1)D black hole case is discussed.
gr-qc↗
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.
gr-qc↗
Are Black Holes Springy?
A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $Ω_+$ can be used to define an effective spring constant, $k=mΩ_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = κ$, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2πT = κ- k$. Hooke's law, in the extremal limit, provides the force $F = 1/4$, which is consistent with the conjecture of maximum force in general relativity.
gr-qc↗
Relativistic superfluidity and vorticity from the nonlinear Klein-Gordon equation
We investigate superfluidity, and the mechanism for creation of quantized vortices, in the relativistic regime. The general framework is a nonlinear Klein-Gordon equation in curved spacetime for a complex scalar field, whose phase dynamics gives rise to superfluidity. The mechanisms discussed are local inertial forces (Coriolis and centrifugal), and current-current interaction with an external source. The primary application is to cosmology, but we also discuss the reduction to the non-relativistic nonlinear Schrödinger equation, which is widely used in describing superfluidity and vorticity in liquid helium and cold-trapped atomic gases.
hep-th↗
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.
gr-qc↗
On Spin-Statistics and Bogoliubov Transformations in Flat Spacetime With Acceleration Conditions
A single real scalar field of spin zero obeying the Klein-Gordon equation in flat space-time under external conditions is considered in the context of the spin-statistics connection. An imposed accelerated boundary on the field is made to become, in the far future, (1) asymptotically inertial and (2) asymptotically non-inertial (with an infinite acceleration). The constant acceleration Unruh effect is also considered. The systems involving non-trivial Bogoliubov transformations contain dynamics which point to commutation relations. Particles described by in-modes obey the same statistics as particles described by out-modes. It is found in the non-trivial systems that the spin-statistics connection can be manifest from the acceleration. The equation of motion for the boundary which forever emits thermal radiation is revealed.
gr-qc↗