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극한상황에서의 물질 : 쿼크물질에서 차가운 원자까지

극한상황에서의 물질 : 쿼크물질에서 차가운 원자까지. 2006. 11. 1 연세대학교 부산대학교 물리학과 홍덕기. Introduction: Symmetries in Physics. Symmetry is beauty : Symmetry is simple:. Ground state is asymmetric : Spontaneous Symmetry Breaking At low energy symmetry is broken Highly excited states are symmetric.

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극한상황에서의 물질 : 쿼크물질에서 차가운 원자까지

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  1. 극한상황에서의 물질: 쿼크물질에서 차가운 원자까지 2006. 11. 1 연세대학교 부산대학교 물리학과 홍덕기

  2. Introduction: Symmetries in Physics • Symmetry is beauty: • Symmetry is simple:

  3. Ground state is asymmetric: Spontaneous Symmetry Breaking At low energy symmetry is broken Highly excited states are symmetric Why nature isn’t symmetric?

  4. Order parameter and Phase Transition:L. D. Landau

  5. Development of Physics • Microscopic theory : more symmetric: • Space and Time -> Spacetime, Lorentz Symmetry. • Electromagnetism+Weak interaction -> Electroweak interaction • Hadron Dynamics and Spectroscopy -> QCD, gauge symmetry • Emergent phenomena: Matter under extreme conditions 1.Spin wave in ferromagnet 2. Superfluid , Superconductivity 3. Quark matter, Cold atoms

  6. How symmetries are broken? • Dynamical • QCD: • Superfluid : • Superfluid , Superconductor : • Electroweak Symmetry: LHC, Tevatron, … • Supersymmetry • Technicolor • Little Higgs

  7. Quantum Chromodynamics • Basic building blocks of matter are quarks and electrons • QCD is one pillar of the standard theory of elementary particles: • Confinement and chiral symmetry breaking: • It successfully explainswhy isolated quarks are unseen and why pions and kaons are so lighter than baryons and no mirror particles exist.

  8. Asymptotic Freedom (Gross-Wilczek-Politzer, Nobel prize 04)

  9. Quark Matter : Prediction of QCD

  10. Evidences: Lattice, Exp’s, Compact Stars Karsch et al at but

  11. When , Sign Problem : • Fordor and Katz: reweighting method:

  12. Experimental Program • AGS @ BNL • Si, Au Beams • 2 ~ 15 AGeV • SIS @ GSI • Bi, Au, Ni Beams • max. 2 AGeV • SPS @ CERN • S, Pb Beams • max. 158 AGeV • RHIC @ BNL • Au Beam • 200 AGeV • LHC @ CERN • - 5.5 TeV • SIS200 @ GSI • - max. 30 AGeV

  13. Comparison with Model Hadronic models Model with phase transition A (possible) sharp maximum can only be accommodated in a model with a phase transition

  14. Compact stars

  15. Cosmic X-rays May Reveal New Form of Matter • RX J1856.5-3754 and 3C58:By Chandra and HST, RX J1856 has T=700,000 K and R= 7miles. Pulsar 3C58 has a too cold core

  16. Cosmic Rays (E. Witten) • AMS-02 Experiment

  17. Properties of Quark Matter • Quark matter is a superconductor: • Low-lying modes has a gap: superfluidity or superconductivity

  18. Various phases of quark matter • 2CS phase at an intermediate density • Color-Flavor Locking (CFL) at • LOFF or gSC when • Gap • for intermediate density, • for high density (HMSW, 00; HLMSS, 03) • Critical Temp.

  19. Color-Flavor-Locked Phase(Alford+Rajagopal+Wilczek, 99) • Symmetry breaking pattern • Particle spectrum 9 quarks -> octet + singlet 8 gluons -> 8 massive vector mesons New degrees of freedom: 8 (pseudo) Goldstone bosons + 1 superfluid mode

  20. Phase continuity(Schaefer+Wilczek, 99) • Higgs phase = confinement phase • Skyrme picture (super qualiton): • DKH+Rho+Zahed(99);DKH+Hong+Park(01) • It provides a new way of calculating the gap

  21. Positivity of QCD at Asymptotic Density: CFL is exact(DKH+HSU, 02) • High Density Effective Theory (DKH, 00): an EFT near Fermi surface • Vafa-Witten theorem: vector symmetry except baryon number is not broken • A solution to the sign problem(DKH+Hsu, 02)

  22. Cold Atoms • BEC (Nobel prize, 01) • Superfluid in a fermionic system ? (magnetic cooling, evaporating cooling, sympathetic cooling,…)

  23. High Temperature Superfluid:Feshbach resonance(Holland et. al, 01; DKH+Hsu,03) • Feshbach resonance • Near detuning, the resonance field is relevant • Gap and Critical temperature:

  24. Have we seen it?(Ohara et. al, Science 02) For at

  25. Conclusion • Symmetry as a guiding principle in physics • Matter is composed of fermions -> Symmetry breaking by fermion bilinears • Superfluid of hellium 3, Lithium 6,… • Chiral symmetry breaking in QCD • Superconductors • Emergent phenomena: New degrees of freedom due to spontaneous symmetry breaking • Superfluidity and superconductivity • Quark matter, cold atoms • QCD

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