When freezing cold is not cold enough new

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“When freezing cold is not cold enough - new forms of matter close to

“When freezing cold is not cold enough - new forms of matter close to absolute zero temperature” Wolfgang Ketterle Massachusetts Institute of Technology MIT-Harvard Center for Ultracold Atoms 9/2/09 Meridian Lecture Space Telescope Science Institute Baltimore

Quantum Gases The coldest matter in the universe

Quantum Gases The coldest matter in the universe

What is temperature? A measure of energy One form of energy is motion (kinetic

What is temperature? A measure of energy One form of energy is motion (kinetic energy).

Cold particles move slowly Hot particles are fast

Cold particles move slowly Hot particles are fast

What is the lowest temperatures possible?

What is the lowest temperatures possible?

Zero degree Kelvin (-273 degrees Celsius, -460 degrees Fahrenheit) is the zero point for

Zero degree Kelvin (-273 degrees Celsius, -460 degrees Fahrenheit) is the zero point for energy

The highest temperature is infinite (In principle it is possible for particles to have

The highest temperature is infinite (In principle it is possible for particles to have arbitrarily high kinetic energies – until they become so heavy (due to E=mc 2) that they from a black hole – at the Planck temperature of 1032 K)

What is the difference in temperature between summer and winter? 20 %

What is the difference in temperature between summer and winter? 20 %

How cold is interstellar space? 3 K

How cold is interstellar space? 3 K

How cold is it in our laboratories? Nanokelvin: A billion times colder than interstellar

How cold is it in our laboratories? Nanokelvin: A billion times colder than interstellar space

Why can you make new discoveries at cold temperatures?

Why can you make new discoveries at cold temperatures?

What happens to atoms at low temperatures? They slow down 600 mph (300 m/sec)

What happens to atoms at low temperatures? They slow down 600 mph (300 m/sec) 1 cm/sec They march in lockstep

Matter made of waves!

Matter made of waves!

Population per energy state What is Bose Einstein Condensation? Bose-Einstein distribution T=Tc Energy

Population per energy state What is Bose Einstein Condensation? Bose-Einstein distribution T=Tc Energy

Population per energy state What is Bose Einstein Condensation? T<Tc Condensate! Bose-Einstein distribution Energy

Population per energy state What is Bose Einstein Condensation? T<Tc Condensate! Bose-Einstein distribution Energy

Population per energy state What is Bose Einstein Condensation? T<Tc Condensate! Bose-Einstein distribution Energy

Population per energy state What is Bose Einstein Condensation? T<Tc Condensate! Bose-Einstein distribution Energy

Ordinary light Photons/atoms moving randomly Laser light Photons/atoms are one big wave

Ordinary light Photons/atoms moving randomly Laser light Photons/atoms are one big wave

* 1925

* 1925

Gases (Atoms and Molecules) Black-Body Radiation “Photons” Max Planck

Gases (Atoms and Molecules) Black-Body Radiation “Photons” Max Planck

The cooling methods • Laser cooling • Evaporative cooling

The cooling methods • Laser cooling • Evaporative cooling

Hot atoms

Hot atoms

Hot atoms Laser beams

Hot atoms Laser beams

Hot atoms Fluorescence Laser beams

Hot atoms Fluorescence Laser beams

Fluorescence Laser beams If the emitted radiation is blue shifted (e. g. by the

Fluorescence Laser beams If the emitted radiation is blue shifted (e. g. by the Doppler effect) ….

Cold atoms: 10 – 100 K Fluorescence Laser beams Chu, Cohen-Tannoudji, Phillips, Pritchard, Ashkin,

Cold atoms: 10 – 100 K Fluorescence Laser beams Chu, Cohen-Tannoudji, Phillips, Pritchard, Ashkin, Lethokov, Hänsch, Schawlow, Wineland …

Laser cooling 2. 5 cm

Laser cooling 2. 5 cm

Evaporative cooling

Evaporative cooling

Phillips et al. (1985) Pritchard et al. (1987)

Phillips et al. (1985) Pritchard et al. (1987)

One challenge … experimental complexity

One challenge … experimental complexity

Sodium laser cooling experiment (1992)

Sodium laser cooling experiment (1992)

Sodium BEC I experiment (2001)

Sodium BEC I experiment (2001)

Dan Kleppner Tom Greytak Dave Pritchard

Dan Kleppner Tom Greytak Dave Pritchard

I. I. Rabi Ph. D Norman Ramsey Ph. D Dan Kleppner Ph. D Dave

I. I. Rabi Ph. D Norman Ramsey Ph. D Dan Kleppner Ph. D Dave Pritchard Postdoc Bill Phillips Ph. D Eric Cornell Undergraduate Postdoc Wolfgang Ketterle Randy Hulet Carl Wieman

Key factors for success: • Funding • Technical infrastructure • Excellent collaborators • Tradition

Key factors for success: • Funding • Technical infrastructure • Excellent collaborators • Tradition and mentors

How do we show that the Bose-Einstein condensate has very low energy?

How do we show that the Bose-Einstein condensate has very low energy?

The condensate • a puff of gas • 100, 000 thinner than air •

The condensate • a puff of gas • 100, 000 thinner than air • size comparable to the thickness of a hair • magnetically suspended in an ultrahigh vacuum chamber

How to measure temperature? Gas Effusive atomic beam Kinetic energy mv 2/2 = k.

How to measure temperature? Gas Effusive atomic beam Kinetic energy mv 2/2 = k. BT/2

How to measure temperature? Gas Effusive atomic beam Kinetic energy mv 2/2 = k.

How to measure temperature? Gas Effusive atomic beam Kinetic energy mv 2/2 = k. BT/2

CCD

CCD

CCD Ballistic expansion: direct information about velocity distribution

CCD Ballistic expansion: direct information about velocity distribution

CCD Ballistic expansion: direct information about velocity distribution Absorption image: shadow of atoms

CCD Ballistic expansion: direct information about velocity distribution Absorption image: shadow of atoms

The shadow of a cloud of bosons as the temperature is decreased (Ballistic expansion

The shadow of a cloud of bosons as the temperature is decreased (Ballistic expansion for a fixed time-of-flight) Temperature is linearly related to the rf frequency which controls the evaporation

Distribution of the times when data images were taken during one year between 2/98

Distribution of the times when data images were taken during one year between 2/98 -1/99

Key factors for success: • Some funding • Technical infrastructure • Excellent collaborators •

Key factors for success: • Some funding • Technical infrastructure • Excellent collaborators • Tradition and mentors

Key factors for success: • Some funding • Technical infrastructure • Excellent collaborators •

Key factors for success: • Some funding • Technical infrastructure • Excellent collaborators • Tradition and mentors • Physical endurance

How can you prove that atoms march in lockstep? Atoms are one single wave

How can you prove that atoms march in lockstep? Atoms are one single wave Atoms are coherent

One paint ball on a white wall Two Paint does not show wave properties

One paint ball on a white wall Two Paint does not show wave properties

One laser beam on a white wall Light shows wave properties

One laser beam on a white wall Light shows wave properties

One laser beam on a white wall Two Fringe pattern: Bright-dark-bright-dark Light shows wave

One laser beam on a white wall Two Fringe pattern: Bright-dark-bright-dark Light shows wave properties

Two condensates. . .

Two condensates. . .

Interference of two Bose-Einstein condensates Andrews, Townsend, Miesner, Durfee, Kurn, Ketterle, Science 275, 589

Interference of two Bose-Einstein condensates Andrews, Townsend, Miesner, Durfee, Kurn, Ketterle, Science 275, 589 (1997)

How do we show that the gas is superfluid?

How do we show that the gas is superfluid?

Rigid body:

Rigid body:

Vortices in nature

Vortices in nature

Spinning a Bose-Einstein condensate The rotating bucket experiment with a superfluid gas 100, 000

Spinning a Bose-Einstein condensate The rotating bucket experiment with a superfluid gas 100, 000 thinner than air Rotating green laser beams Two-component vortex Boulder, 1999 Single-component vortices Paris, 1999 Boulder, 2000 MIT 2001 Oxford 2001 J. Abo-Shaeer, C. Raman, J. M. Vogels, W. Ketterle, Science, 4/20/2001

Current Research BEC on a microchip

Current Research BEC on a microchip

Loading sodium BECs into atom chips with optical tweezers 44 cm BEC arrival BEC

Loading sodium BECs into atom chips with optical tweezers 44 cm BEC arrival BEC production T. L. Gustavson, A. P. Chikkatur, A. E. Leanhardt, A. Görlitz, S. Gupta, D. E. Pritchard, W. Ketterle, Phys. Rev. Lett. 88, 020401 (2002). Atom chip with waveguides

Splitting of condensates 1 mm One trapped 15 ms condensate Expansion Two condensates

Splitting of condensates 1 mm One trapped 15 ms condensate Expansion Two condensates

Splitting of condensates 1 mm Trapped 15 ms expansion Two condensates

Splitting of condensates 1 mm Trapped 15 ms expansion Two condensates

Splitting of condensates Two condensates Y. Shin, C. Sanner, G. -B. Jo, T. A.

Splitting of condensates Two condensates Y. Shin, C. Sanner, G. -B. Jo, T. A. Pasquini, M. Saba, W. Ketterle, D. E. Pritchard, M. Vengalattore, and M. Prentiss: Phys. Rev. A 72, 021604(R) (2005).

Splitting of condensates Two condensates Atom interferometry: The goal: Matter wave sensors Use ultracold

Splitting of condensates Two condensates Atom interferometry: The goal: Matter wave sensors Use ultracold atoms to sense Rotation Navigation Gravitation Geological exploration

Current Research Cold molecules Cold fermions

Current Research Cold molecules Cold fermions

Can electrons form a Bose-Einstein condensate and become superfluid (superconducting)? Two kinds of particles

Can electrons form a Bose-Einstein condensate and become superfluid (superconducting)? Two kinds of particles • Bosons: Particles with an even number of protons, neutrons and electrons • Fermions: odd number of constituents Only bosons can Bose-Einstein condense!

Can electrons form a Bose-Einstein condensate and become superfluid (superconducting)? Two kinds of particles

Can electrons form a Bose-Einstein condensate and become superfluid (superconducting)? Two kinds of particles • Bosons: Particles with an even number of protons, neutrons and electrons • Fermions: odd number of constituents Only bosons can Bose-Einstein condense! How can electrons (fermions) condense? They have to form pairs!

Can we learn something about superconductivity of electrons from cold atoms? Yes, by studying

Can we learn something about superconductivity of electrons from cold atoms? Yes, by studying pairing and superfluidity of atoms with an odd number of protons, electrons and neutrons

BEC of Fermion Pairs (“Molecules”) These days: Up to 10 million condensed molecules Boulder

BEC of Fermion Pairs (“Molecules”) These days: Up to 10 million condensed molecules Boulder Innsbruck MIT Paris Rice, Duke Nov ‘ 03, Jan ’ 04 Nov ’ 03 March ’ 04 M. W. Zwierlein, C. A. Stan, C. H. Schunck, S. M. F. Raupach, S. Gupta, Z. Hadzibabic, W. K. , Phys. Rev. Lett. 91, 250401 (2003)

Gallery of superfluid gases Atomic Bose-Einstein condensate (sodium) Molecular Bose-Einstein condensate (lithium 6 Li

Gallery of superfluid gases Atomic Bose-Einstein condensate (sodium) Molecular Bose-Einstein condensate (lithium 6 Li 2) Pairs of fermionic atoms (lithium-6)

Ultracold atoms A “toolbox” for designer matter Normal matter • Tightly packed atoms •

Ultracold atoms A “toolbox” for designer matter Normal matter • Tightly packed atoms • Complicated Interactions • Impurities and defects

Ultracold atoms A “toolbox” for designer matter Matter of ultracold atoms • 100 million

Ultracold atoms A “toolbox” for designer matter Matter of ultracold atoms • 100 million times lower density • Interactions understood and controlled • no impurities • exact calculations possible Need 100 million times colder temperatures