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The CMB according to WMAP
Image of Universe at recombination(atom formation, not itself a phase transition)
Lumpiness due to earlier transition
300,000years
3minutes
1 micro-second
1 pico-second
Recombination:Birth of atoms
Nucleosynthesis:Birth of nuclei
Quark-hadronphase
transition
Electroweak phase transition:
Birth of matter?Inflation?
Birth of Stucture?
Hot and Dense Hadronic MatterCollide heavy nuclei at high energies to create …
… and probe the quark-hadronphase transition
Recreate the first 10-6 seconds …Properties described by
string theory ideas:
viscosity, jet quenching, …?
AdS/CFT Approach to QGP
• Gauge theories in 4 dimensions related to (suitably chosen) gravity/string theory in 5 dimensions:
g: = 5 A
• Rigorous for N= 4 supersymmetry(scale-invariant conformal field theory)
• Heuristic for realistic QCD• Interest because
strong gauge coupling weak string coupling• Reliable calculations for strongly-coupled QGP?
Black Holes in 5 Dimensions
• Consider 5-dimensional AdS space, radius b, metric:
4 Newton constant
• Black holes stable if temperature
T > T1 = 1/b
• Outer horizon of BH = r+
• Consider two limits: b << r+, b >> r+ JE, A.Ghosh, Mavromatos
Black Hole Equation of State
• High-temperature limit b << r+
• Partition function
• Effective potential
• van der Waals equation of state
• Suggestive of phase transition
• Approximate density, pressure
JE, A.Ghosh, Mavromatos
Combined Picture of Transition
• Reminiscent of lattice results
• New insight into underlying dynamics?
• Calculational tool for QGP?
JE, A.Ghosh, Mavromatos
AdS/CFT for N = 4 SUSY Gauge Theory
• N = 4 SUSY QCD has fixed coupling • Rigorous AdS/CFT correspondence at
large (∞, 1/ corrections), large Nc
• Can be used to calculate Wilson loops• Related to static and dynamic quantities• Promising comparison with knowledge of
QCD for T ~ 1.2 to 2.5 Tc
• Challenge to extend to realistic QCD
Viscosity in N = 4 SUSY Gauge Theory
• Potentially interesting for cosmological QCD transition: not yet explored
Very small at large coupling
Lower thanother fluids!
Kovtun, Son, Starinets
Comparison with Lattice Calculations
• N = 4 result similar to lattice for T ~ 2 Tc
• But trace anomaly ≠ 0 QCD not conformal
Electroweak Phase Transition
• Second order in the Standard Model for mH > 114.4 GeV
• Strong first order needed for baryogenesis at the electroweak scale
• Not enough CP violation anyway in the Standard Model
• Both problems may be solved by SUSY
Generating the matter in the Universe
• Need difference between matter, antimatter
C, CP violation seen in laboratory• Need matter-creating interactions
present in unified theories – not yet seen• Need breakdown of thermal equilibrium
possible in very early Universe
e.g., in first-order phase transition
Sakharov
Could a first-order electroweak transition be the culprit?
Electroweak Transition in SUSY
• First order electroweak phase transition if additional light scalar
• Most plausible candidate: light stop• Beware of development
of stop v.e.v.• Parameter space very
tightly constrained• Higgs and/or stop
close to discoveryQuiros
Baryogenesis in SUSY
• Additional sources of CP violation
• ‘Easy’ to get sufficient baryon/entropy
• Favours relatively
light CP-odd Higgs
• Modest CP-violating
phase is enough
Quiros
Implications of SUSY Baryogenesis
• mH < 120 GeV, 120 GeV < mstop < mt
• 5 < tan < 10, small stop mixing
• CP-violating phase ~ 0.1
• Important limits from electric dipole moments
Balazs, Carena, Menon, Morrissey, Wagner
Implications for SUSY Dark MatterParameter region changeswith CP violating phase
Scattering may be reduced
as CP-violating phase
Balazs, Carena, Menon, Morrissey, Wagner
Low-Energy Effects of CP Phases
Bs
b s
Bu
Different
regions
allowed for
different
phases … … and hence
ACP in
b sJ.E. + Lee + Pilaftsis: arXiv:0708.2078
Cosmological Inflation
• Theory to explain the size, age & uniformity of the Universe
• Period of (near) exponential expansion driven by scalar field energy (1)
• Quantum effects → CMB anisotropies, origins of structures
• Subsequent reheating → matter (2)• Then matter-antimatter asymmetry generated
Origin of Structures in Universe
Small quantum fluctuations: one part in 105
Gravitational instability: Matter falls into
the overdense regions
Convert into matter with varying density
The CMB according to WMAP
Image of Universe at recombination(atom formation, not itself a phase transition)
Lumpiness due to earlier transition
• Upper limit on Hubble expansion rate during inflation
Higgs Mass and Inflation
• Upper limit on reheating temperature from metastability
Espinosa, Giudice, Riotto
A Phase Transition in the Future?
• Our electroweak vacuum may be unstable if mH small (hinted by electroweak data)– Renormalization by top quark drives Higgs
self-coupling < 0 at large <H>
• Metastable vacuum, lifetime = f(mH, mt, s)– mH too small would have decayed– mH too large will ‘never’ decay– mH, mt, s just right: Big Bang Big Crunch
On our Way to a Big Crunch?
Renormalization by top quark coupling
New vacuumwith 0|H|0 >
mH =125120115105GeV
Big Crunch!Arkani-Hamed, Dubovsky, Salvatore, Villadoro
Is there a Big Crunch in Our Future?
Present errors
Big Crunch for mH = 114.4 GeV
Future errors
Eternal expansion
Big Crunch!Big Crunch allowed @ 1.5
Arkani-Hamed, Dubovsky, Salvatore, Villadoro
Outlook
• Phase transitions in early universe might have been very important:– Origin of structures– Origin of matter– Size of Universe, …(and there may be another in the future)
• Quark-hadron transition only one directly accessible to experiment
• Go to it!