第19回金茶会KEK

June 2008/7/4

レーザーで何ができるの？

KEK Toshiki Tajima(also at JAEA)

Acknowledgment of collaborators: T. Takahashi, K.Homma, T.Tauchi, K.Kondo, T,Omori, J. Urakawa, K.Fujii, M. Nozaki, S.Bulanov, M. Fujiwara, P.Chen, T.Nomura, G. Mourou, D. Habs, Q. Niu, Y.Kato, K.Ueda, M.Kando, A.Pirozhkov, Y.Fukuda,F.Takasaki, K.Nakajima, R.Hajima, T.Hayakawa, Q.Niu, K.Nasu, A.Suzuki,Y.Takahashi,T.Ebisuzaki

• Quantum mechanics -- Relativity• Particle physics in infinitesimally small

distance (such as Planck distance) vs. ‘macroscopic’ structure of vacuum?

• Warping of vacuum, Structure and property of vacuum

• Extreme Field Science; Laser and Accelerator

• Single particle vs Collective effects• Special vs General Relativity

What is vacuum? What is relativity?

An observer in a crystal as vacuum Phonon is an excitation of vacuum Strong field breaks vacuum↓ ↓ ↓

「⾊即是空」

「空即是⾊」

「（真）空」 Photon is a distortion of vacuum e+e- pair production out of vacuum

4

Lasers

(KEK)

(Tajima,Mourou,2002)

V. Yanovsky, et al., Opt. Express 16 2109 (2008)

5

What is collective force？

Individual particle dynamics vs. Coherent movement

Collective accelerationCollective radiation (N2 radiation)

Collective ionization (N2 ionization)

How can a Pyramid have been built?

Vacuum Breakdown at Schwinger Field

+e

−e0>E

w =

1π 2

αcD 4

EEs

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟

2

exp −πEs

E⎛ ⎝ ⎜

⎞ ⎠ ⎟

2moc2

Julian Schwinger

Note the similarity of Schwinger expression to the Keldysh atom ionization ⇐from the ‘structure’ of vacuum / atom

Pair Creation: Vacuum boiling

8

+⎥⎦⎤

⎢⎣⎡ ++⎥⎦

⎤⎢⎣⎡ +−=+

− 22328

4222

4

21 )~(

213)(4

3151)~(

47)(

901)( FFFF

mFFF

mAL NLOLO

loop

πα

πα

παπ

πα

παπ

μ

∑=

+−

⎥⎦

⎤⎢⎣

⎡++

⎥⎦⎤

⎢⎣⎡ +−=+

dui

ss

i

i

aNLOLO

loop

GFFGFm

q

FFFm

GAL

,

222228

42

2224

21

)~(2

13)(123151

)~(47)(

901)(

πα

πα

πα

παπ

πα

παπ

μνμ

2222 FqGF s

πα

πα

πα

+→

944,5.15

21 22 ==±≈≈ dudu qqMeVmm

Euler-Heisenberg effective action in constant Abelian field U(1) can be expressed as

If U(1)→U(1) + condensed SU(3) due to self-interacting attractive force of gluons

Focus on only light-light scattering amplitude after the substitution

Check of Euler-Heisenberg yet to come. Any deviation from it? → axion field?; extended fields( such as dark energy, Tajima-Niu, 1997, etc.)?

∑=

±≈=−−

duie

i

i eGmm

qtermsttermnd

,

5.29248

42

724

12

παπ

QCD effect dominates pure QED 1-loop vacuum polarization to light-light scattering

Higher order QED and QCD hep-ph/9806389

422 10)3.03.2(00 GeVGs −±≈πα

<GG>

e-e+

q+q-

4-wave mixing (Lundström et al (2006))

Electron-positron pair production in the laser interaction with the electron beame+ + nγ →γ, γ+nγ' → e+ + e-

(Bula et al (1996); Burke et al (1997))

Some Examples of Vacuum Nonlinearities

Higher harmonic generation through quantum vacuum interaction(Fedotov & Narozhny (2006))

Unruh radiation (Chen&Tajima (1999))

ar

Larmor Radiation

E

Unruh Radiation

E

10

Extra dimensional effect based on Kaluza-Klein theory

PRD 68(2003)106005, A. Ganguly et al.

g55 couples electromagnetic field

4/1 G∝λExtreeeemely small,unless B is extreeeemly large

(K.Homma’s slide,2007)

General Relativity

and Black Holes

Vacuum Emission Under Gravity

Hawking radiation

What is ‘vacuum’? Does ‘something’ emerge from ‘nothing’?「空」＝「色」？ 「混沌」 「秩序」？

13

Radiation via event horizon -- access to zero-point energy --

∑+∞

−∞=

++=k

kkkk uaua )( *φ

∑+∞

−∞=

+++++=

kkkkkkkkk ubububub )( )*2()2()2()2()*1()1()1()1(φ

110||0 /2

)2,1()2,1(

−∝ −

+απωe

bb MM

F

P

Rindler 1x

t

Rindler 2

Minkowski spacetime

Trajectory of observer with a constantproper acceleration α (Rindler observer)

Rindler 1 and 2 are causally disconnected(introduction of an event horizon)

πκ

πα

22=⇔= TkTk BB

Unruh temp.⇔ Hawking temp.

Minkowski spacetime looks as if thermal bathto a Rindler observer via the Bogoliubov trans.

Optical laser as a source of accelerationElectron as an Rindler particle

(K.Homma)

Unruh vs. Larmor radiation

R. Schuetzhold Phys.Rev.Lett.97:121302, 2006

Larmor scatteringUnruh radiation

Correlatedpair radiation

Inertial frame

Rindler frame Strong correlation betweenabsorption and emissiondespite of causal disconnection

G. Unruh PRD 29 1047-1056, 1984

negative frequencymode in Rinder 2

Observerin RIndler 1

No correlated pairin background process

⇒=⇒≈⇒=

eVTkmVEcmWI

B 06.0]/[10]/[10 12217

~10eV (blue shift in lab. frame)

e- e-

(Chen, Tajima,1999)

Event Horizon Analog?,…..

T.Philbin et al., Science 319, 1367 (2008)

Flying Mirror for Femto-, Atto-, … Science

(KEK)

Insulator

Tajima & Dawson (1979)

Plasma cavity

RF cavity

E-field max ≈ 10 MV/mR>Rmin Synchrotron radiation

Cathode

AnodeACCELERATING WAVEGUIDE

λ/2

λ

INJECTOR

Ultrahigh axial electric fieldsCompact electron acceleratorsPlasma wakefields:E > 10 GV/m, fast wavesPlasma channel: Guides laser pulseand supports plasma wave

Plasma Waveguide

Plasma Wave Laser PulseElectron Bunch

Classical and LWF Accelerators

(Bulanov)

20'' 4

-ph

phph

c vc v+

ω = ω≈ γ ω

Laser x Laser: EM Pulse Intensification and Shortening

by the Flying Mirror

2''6max

0ph

I DI

⎛ ⎞≈ κ γ ⎜ ⎟λ⎝ ⎠

-3phκ γ:

3D Particle-In-Cell Simulation

(Bulanov, Esirkepov, Tajima, 2003)

Colliding two lasers for the flying mirror experiment

tp = -750 fstp = -250 fstp = -150 fstp = -050 fstp = 0

Vacuumfocus

Jetcenter630 μm

Driver200 mJ, 76 fs

Source12 mJ

Side View

Top View Relativistic Microlens

(Kando et al 2007)

The driver and source must carry 10 kJ and 30 J, respectively (Parameters on the order of ELI and HiPER Lasers)

Reflected intensity can approach the Schwinger limit

It becomes possible to investigate such the fundamental problems of nowadays physics, as e.g. the electron-positron pair creation in vacuum and the photon-photon scattering

Laser Energy & Power Required to Achieve the Schwinger Field

h

2 3e

Q E D

m cE

e=

( )L21

5 1416 64

F F F F F F F Fa b a b bg dm

a b a b a b gd

k

p p鴿

= - -・・

The critical power for nonlinear vacuum effects is P2 2245

4

QEDcr

cE lp

a p=

for it yields1 ml m= P 242.5 10cr Wｻ ｴLight compression and focusing with the FLYING MIRRORS yieldsfor with the driver power2

0/ 4

phl l g=

0 phg=P P 30

phg ｻ 10cr PWｻP

(Mourou, Tajima, Bulanov, 2006)Laser self-focuses in vacuum with RE!

22

Homma proposes: experimental test

2204 RneET πε

γ=

γνRt ≈Δ

nRt

ncl

γβδ =Δ≈

e-

Measure instantaneous variation of refractive indexin Electro-Optical crystal by external electric fields.

e-

z

z

xy y

x

γRx ≈Δ

))5.0(tan(cos 3/11−≈Δ Ry

TEO Erfn )(=δ

Re

nrfln EO

λβεδδ

λπδ 3

02)(2

==Γ

R

Phase retardation

(Homma, 2007)

23

Diffraction patterns with a thin wire of 50μmφ

Horizontal wire Tilted wire Vertical wire

Fourier transformation of Gaussian is Gaussian with smaller waist.

Pictures taken by wide dynamic range CMOS camera

No wire

Spatially homogenous interferometer:Intensity modulation of (A+δA)2 gives contrast ~ δA/A in everywhere.

Outer diffraction sampling gives contrast close to infinity !

Gaussianprofile

(Homma, 2007)

Past attempts via non-collider method exploring new fields such as axion……

A.Chou et al.,PRL (2008) observed no signal so far (Note:claim of axion by PVLAS was withdrawn)

coup

ling

mass

storage ringγ＝ 16000

γraysPolarized e+、・・・

IR FEL

Photonuclear physicsPhotonuclear transmutationPolarized positrons for collider

FELSPring-8８GeV e-beams X laser(FEL)

New Paradigm for nuclear physics and

nuclear energy

Example of Crossing of Laser and Beams

(Ejiri et al.)(Omori et al.)

Kansai Research Establishment = Lasers ⊗ SPring8

Intense Laser at ATF2 Suggestedlaser x accelerator

• Laser Compton Gamma Raysnuclear resonance fluorescence, Moessbauer spectroscopy, detection of nuclear matter, EW/S coupled physics, gamma-gamma collider simulator

・ High Y PhysicsQED nonperturbative regimes, near-Schwinger field physics, vacuum polarization and nonlinearities

・ Quantum Controlcoincided modulation and scattering, beam manipulation, femtosecond diagnosis, zeptosecond spectroscopy

ATF2 Configuration @KEKElectrons with γ ‘see’ the EM fields compactified andIntensified by a factor of γ (and intensity I by γ2）

γ~ 2.5 x 103

I = 1022 W/cm2 ----- I = 1029 (~ Schwinger field)

Conclusions• Extreme fields of laser: a new tool for particle and

field physics• Beyond collider paradigm?• Laser x Accelerator: window into new regimes• Is anything beyond standard theory? Verification of

Euler-Heisenberg theory, axions, dark energy,…?• Is c constant?• Collective effects important for laser acceleration,

vacuum study, …• More study of relativity expected, needed

宇宙のプラズマ線型加速器(beyond 1020 eV)？

ご清聴有難うございました。

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