PHYS 34 Modern Physics Ultracold Atoms and Trappe Ions Today and Mar.3 Contents: a) Revolution in physics nd Quantum revolution b) Quantum simulation, measurement, and information c) Atomic ensemble and quantum statistical (refer to Charpter0) d) Cooling and trapping of 6 Li fermions e) Quantum simulation with ultracold atoms f) Quantum measurement with ultracold atoms g) Quantum Information Basis h) Cooling and Trapping Charged Particles i) Preparation, Manipulation and Detection of 7 Yb + j) Trapped Ion Quantum Computers k) Quantum Network Revolution in Physics Revolution in Physics must unifies seemingly unrelated phenomena. Mechanical Revolution: Unified falling apples on earth and the planets motions in sky Quantum Revolution: Unified particle and wave EM Revolution: Unified electricity, magnetism, and light Relativity Revolution: Unified space, time and gravity What is the second quantum revolution? Think different from Particle-Wave Duality Simulation of Nature using Quantum Software and Hardware (original ideas from Richard Feynman) wave-like : flying in the space, messenger of the world------ Information Nature isn t classical, if you want to make a simulation of nature, you d better make it quantum mechanical. Software from quantum principles (quantum information) How can we simulate the quantum mechanics?.can you do it with a new kind of computer - a quantum computer? Hardware from quantum devices (quantum matter) particle-like : localized in the space, elements for the world------ Matter Second Quantum Revolution unifies Matter and Information at Quantum Level! Particle-Wave duality Matter Information duality Need Quantum Computer!
Toys for Second Quantum Revolution My Favorite Toys : Trapped Atoms and Ions We can create states of quantum coherent or entangled matter and energy that likely existed nowhere else in the Universe. These new man-made quantum states have wide application to the development of computers, communications systems, sensors and compact metrological devices. ---- by J.P.Dowling and G.J.Milburn 6 Li Atom: Fermi Condensation 40 Ca + Ion: Ground State Interaction, Spin, Dimensionality, Filling, Impurity, Coherence All Tunable! Developed to: Atomic Matter Physics, Quantum Simulator, Quantum Sensors, Atomtronics Trapped Quantum Particles (Historical) Trapped Atoms and Ions 989 Nobel Prize: Ion trap isolating single quantum particle. Hans Dehmelt Wolfgang Paul 997 Nobel Prize: Laser cooling and trapping atoms. Steven Chu Claude Cohen-Tannoudji William Daniel Phillips 00 Nobel Prize: Bose-Einstein condensation in dilute gases Eric Cornell, Carl Wieman, Wolfgang Ketterle 0 Nobel Prize: Manipulation of individual quantum systems Serge Haroche and David J. Wineland 7 US Physicists (4 from NIST/JILA), France, Germany Degenerate Fermi Gas and Condensation Hybrid Atom-photon Interferometer Ion Trap Quantum Computer And Network
Pauli Exclusion Principle Today and Mar.3 Contents: a) Revolution in physics nd Quantum revolution b) Quantum simulation, measurement, and information c) Atomic ensemble and quantum statistical (refer to Charpter0) d) Cooling and trapping of 6 Li fermions e) Quantum simulation with ultracold atoms f) Quantum measurement with ultracold atoms g) Quantum Information Basis h) Cooling and Trapping Charged Particles i) Preparation, Manipulation and Detection of 7 Yb + j) Trapped Ion Quantum Computers k) Quantum Network Fundamental principle -- Pauli Exclusion Principle Any fundamental particles with Odd/ spin can not have the same set of quantum numbers in a quantum system. spin=0,,,3,4.. spin=/,3/,5/... How to Label an Atomic State Now we have seven quantum numbers for a certain atomic state. ( n, l, m l, s, m s, j, m j, I, m I, F, m F ) e orbital e spin e total nuclei spin total # (for all electrons): (for the outer electrons): / Now I =, what is F, m F? Mixture of Spin Up/Down 6 Li Atoms Hyperfine Structure in a Magnetic Field p B 0 670 nm E 3 s Ground State(s s ):J=/ Level Spin ½ Up Nuclear Spin: I= 5 6 4 =, Level Spin ½ Down =, 0, States High B-Field Seeking----Requires Optical Trap
6 Li Atoms for Fermionic Condensation Strong Interacting Systems in Nature High-Tc Supercond uctor Black Holes in String Theory Neutron Stars Ultracold Fermi Gas Universal Properties Quark- Gluon Plasma All fundamental material particles are fermions: Fermionic condensation plays more significant roles in many-body physics No Interaction (idea gas) Strong Interaction Scaling Invariance Universal Properties?? Trivial Universality (PV=nRT) Many-body Strong Interaction From0 3 K to 0-7 K George Bertsch s Problem ( a problem for neutron star) L T=700 K MOT Beam L -V 0 R Two spin component interacting via s-wave quantum collisions. -V 0 R a L R 0 The only length scale is the interparticle spacing L (n,t). All thermodynamic and dynamic properties are only determined by density and temperature Free and Forced Evaporative Cooling T < μk N=00,000 Zeeman Slower MOT Slowing Beam T=50 μk N=500 Million Optical Trap U = 0.7mK I =MW/cm Size ~ 50 μm
Optical Dipole Trapped Fermi Gas S-wave scattering Feshbach Resonance agnet coils B g 3 u =, =, 0 electron spin, nuclear spin Optical Trap Loading
Forced Evaporation Force Evaporative Cooling Weakly Interacting Regime cooling@ 330 G for weakly interacting Fermi Gas Strongly Interacting Regime cooling@ 834 G for strongly interacting Fermi Gas High-Field Imaging Phase Diagram for 6 Li Ultracold Fermi Gas BEC Unitary BCS
Strongly Interacting Degenerate Fermi Gases BEC-BCS crossover: A pure theoretical problem in condensed matter physics before 00. Become real experiments in atomic physic after 00 0.0 U 0, T/T F = 0.45 0.00 U 0, T/T F = 0.8 Ballistic Expansion Gas dynamics Hydrodynamic Expansion- Fluid Dynamics Noninteracting Fermi Gas Fermi Condensation or Strongly interacting Fermi gas