# Critical Acceleration and Vacuum rafelski/PS/ Acceleration and Vacuum Structure ......

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Critical Acceleration andVacuum Structure

Johann RafelskiDepartment of Physics, The University of ArizonaCharles A Whitten Memorial Symposium Dec 15/16 2011

I discuss foundational ultra-high acceleration physics challenges arising in the contextof relativistic laser pulse interactions: pulse interaction with the quantum vacuum, theopportunity to improve understanding of inertia, quantum vacuum as modern dayaether, and the materialization of pulse energy directly into high energy particles.

Supported by US DoE Grant: DE-FG02-04ER41318

Overview

1 Introduction

2 Critical acceleration

3 Fundametal Interaction

4 Mach and Inertia, Aether Quantum Vacuum

5 High energy particles

graphics credit to: S.A. Bulanov, G. Mourou, T. Tajima

The 21st Century Foundational Physics Challenges How does the structured quantum vacuum control inertia,

and many other laws of physics Is there a deeper understanding of time?

Rle of the Universe expansion in defining time? What is the cosmological dark energy,

= (2.4meV)4~3c5 = 4.3keVc2/cm3

Is this excited state quantum Vacuum with non-zero pointenergy? If so how can we induce vacuum decay? What isthe magnitude of causal velocity (velocity of light) in thedifferent vacuum states?

What is the origin of grand scales as expressed bya) the Planck mass: MP =

~c/GN = 1.3 1019mproton andb) Higgs VEV h = 254 GeV 1013mneutrino.

Space-time: dimensionality (3+1) (n + 1): n > 3?Fractal dimension n < 3? Lattice? (Mem)brane?

Discovery is driven by new tools: acceleration

1899:Planck units

These scales retain their natural meaning as long as the law ofgravitation, the velocity of light in vacuum and the central equations ofthermodynamics remain valid, and therefore they must always arise,among different intelligences employing different means ofmeasuring. M. Planck, ber irreversible Strahlungsvorgnge. Sitzungsberichte der Kniglich PreuischenAkademie der Wissenschaften zu Berlin 5, 440-480 (1899), (last page)

Critical Planck accelerationIn presence of high acceleration we probe connection betweenforces (interactions) and the structure of space-time. In thatsense there is also a limiting Planck acceleration, which toavoid misunderstanding we term critical acceleration ac .

Einsteins gravity is built upon EquivalencePrinciple: a relation of gravity to inertia(=theresistance to acceleration). Note that wheninteractions are geometrized like gravity instring theories, we are doing away withacceleration. Thus current super-theoriesreally go in direction of removing force. It isquantum physics that allows us today tocreate devices that expose particles toacceleration.

Critical AccelerationCritical acceleration acting on an electron:

ac =mec3

~ 2.331 1029m/s2

This critical acceleration can be imparted on an electron by thecritical Schwinger (Vacuum Instability) field strength ofmagnitude:

Ec =m2ec

3

e~= 1.323 1018V/m

Truly dimensionless unit acceleration arises when we introducespecific acceleration

= acmc2

=c~

Specific unit acceleration arises in Newton gravity at Plancklength distance: G G/L2p = c/~ at Lp =

~G/c. In presenceof sufficiently strong electric field Ec by virtue of the equivalenceprinciple, we probe electrons subject to Planck scale force.

Critical acceleration probably achieved at RHICTwo nuclei smashed into each other from twosides: components partons can be stopped inCM frame within 1 fm/c. Tracks showmultitude of particles produced, as observed atRHIC (BNL).

The acceleration a achieved to stop some/any of the components ofthe colliding nuclei in CM: a yMi . Full stopping: ySPS = 2.9, andyRHIC = 5.4. Considering constituent quark massesMi MN/3 310 MeV we need SPS < 1.8 fm/c and RHIC < 3.4fm/c to exceed ac . Observed unexplained soft electromagnetic radiation in hadronreactions A. Belognni et al. [WA91 Collaboration], Confirmation of asoft photon signal in excess of QED expectations in p interactionsat 280-GeV/c, Phys. Lett. B 408, 487 (1997). Recent suggestions that thermal hadron radiation due to Unruhtype phenomena P. Castorina, D. Kharzeev and H. Satz, ThermalHadronization and Hawking-Unruh Radiation in QCD, Eur. Phys. J. C52, 187 (2007), also Biro, Gyulassy [arXiv:1111.4817]

Other path towards super-critical (Planck) accelerationa = 1(= mec3/~ 2.331 1029m/s2)

Directly accelerated electrons at rest in lab by ultra intenselaser pulse: requires Schwinger scale fieldPresent laser pulse intensity technology misses several ordersof magnitude, further development needed. Shortcut: we canLorentz-boost: to reach the critical acceleration scale today: wecollide a counter-propagating electron with a laser pulse.

Laser pulse in electrons rest frame

Figure shows boost (from left to right) of the force applied by aGaussian photon pulse to an electron, on left counter propagatingwith / cos = 2000. Pulse narrowed by ( cos )1 in thelongitudinal and ( sin )1 in the transverse direction. Correspondsto Doppler-shift:

= ( + ~v nk)as applied to different frequencies making up the pulse.

SLAC95 experiment near to critical acceleration

p0e = 46.6 GeV; in 1996/7 a0 = 0.4,

du

d

= .073[me] (Peak)

Multi-photon processes observed: Nonlinear Compton scattering Breit-Wheeler electron-positron pairs

D. L. Burke et al., Positron production in multiphoton light-by-light scattering, Phys.Rev. Lett. 79, 1626 (1997)

C. Bamber et al., Studies of nonlinear QED in collisions of 46.6 GeV electrons with

intense laser pulses Phys. Rev. D 60, 092004 (1999).

EM Probe of critical acceleration possible todayIZEST, or SLAC,CEBAF: experimentspossible in principle

CEBAF: There is a 12 GeV( = 2400) electron beamThere is a laser teamThere is appropriate highradiation shieldedexperimental hall

Mach, Acceleration Inertia To measure acceleration we need to refer to aninertial frame of reference. Once we know one iner-tial observer, the class of inertial observers is defined.

Before Einsteins relativity, Mach posited, as an alternative toNewtons absolute space, a) that inertia (resistance to acceleration)could be due to the background mass in the Universe, and b) that thereference inertial frame must be inertial with respect to the Universemass rest frame. The latter postulate Einstein called Machs principle.

Any observer inertial wrt CMB frame qualifies: Machs fixed stars". GR and later Cosmology motivated by Machs ideas, yet Einsteinnearly eliminated acceleration: geometrization of gravity means thatdust of GR point masses is in free fall.

Inertia, the resistance to acceleration requires presence ofnon-geometric forces and/or extended quantum matter leading torigid extended material body.

QFT provides the quantum vacuum, the Aether, as Machs frame.

Maxwell, Lorentz and Inertia: ad-hoc combination

The action I comprises three elements: (F A A)

I = 14

d4x F 2 + q

pathd

dxd

A + mc2

pathd(u2 1).

Path is fixed at the end points assuring gauge-invariance.

The two first terms upon variation with respect to the field, produceMaxwell equation including radiation emission in presence ofaccelerated charges.

The second and third term, when varied with respect to the form ofthe material particle world line, produce the Lorentz force equation:particle dynamics in presence of fields.

Maxwell and Lorentz equations which arise NEED NOT BECONSISTENT, the form of I dictated by gauge- andrelativistic-invariance. Many modifications are possible. There is noreference to Machs inertial frame allowing definition of acceleration.

Gravity and other interactions not truly unified

J = Ig +1

8G

d4xg R

There are acceleration paradoxes arising combining gravity andelectromagnetism:

Charged electron in orbit around the Earth will not radiate ifbound by gravitational field, but it will radiate had it been bendinto orbit by magnets.

A free falling electron near BH will not radiate but an electronresting on a surface of a table should (emissions outsideobservers horizon.

A micro-BH will evaporate, but a free falling observer may notsee this. Is the BH still there?

One is tempted to conclude that we do not have a theoryincorporating acceleration. New Physics Opportunity if we cancreate unit strength (critical) acceleration.

Better foundational theory not around the corner

Old idea: geometrize EM theory: 5-d Kaluza-Klein.

EM potential part of 5-metric. To lowest order in charge,Lorentz force arises from 5-d geodetic. Hilbert-Einstein 5-daction reduces to 4-d Einstein-Maxwell action.

Pro: Any geometric EM theory has ther and is Machian justlike GR; charge is a property of the ther; the missing degreesof freedom appear in 5th dimension.

Con: Lack of understandings of dynamics in 5-d extradimension, solutions arbitrary. No experiment showinggeneralized equivalence principle justifying use of 5-d geodetic.

Should the generalization of Maxwell-Lorentz be geometric,critical acceleration experiments will be capable to explore thisunification.

Einsteins Aether as an inertial frame of referenceAlbert Einstein at first rejected ther as unobservable when formulatingspecial relativity, but eventually changed his initial position, re-introducingwhat is referred to as the relativistically invariant ther. In a letter to H.A. Lorentz ofNovember 15, 1919, see page 2 in Einstein and the ther, L. Kostro, Apeiron, Montreal (2000). he writes:It would have been more correct if I h