Lene Hau

Lene Hau

Lene Hau in her laboratory at Harvard
Born (1959-11-13) November 13, 1959
Vejle, Denmark
Residence Boston U.S.
Nationality Danish
Fields Physics and Nanotechnology
Institutions Harvard University
Rowland Institute for Science
Alma mater Aarhus University
Doctoral students Naomi Ginsberg, Christopher Slowe, Zachary Dutton, Anne Goodsell, Trygve Ristrophe
Known for Slow light, Bose–Einstein condensates, nanotechnology, quantum optics
Notable awards Ole Rømer Medal
George Ledlie Prize
MacArthur Fellowship
Rigmor and Carl Holst-Knudsen Award for Scientific Research

Lene Vestergaard Hau (born November 13, 1959 in Vejle, Denmark) is a Danish physicist. In 1999, she led a Harvard University team who, by use of a Bose-Einstein condensate, succeeded in slowing a beam of light to about 17 metres per second, and, in 2001, was able to stop a beam completely.[1] Later work based on these experiments led to the transfer of light to matter, then from matter back into light,[2] a process with important implications for quantum encryption and quantum computing. More recent work has involved research into novel interactions between ultracold atom and nanoscopic scale systems. In addition to teaching physics and applied physics, she has taught Energy Science at Harvard,[3] involving photovoltaic cells, nuclear power, batteries, and photosynthesis. As well as her own experiments and research, she is often asked to speak at International Conferences, and is involved in structuring the science policies of various institutions. She was keynote speaker[4] at EliteForsk-konferencen 2013, (Elite Research Conference) in Copenhagen, February 7, 2013, which is attended by government ministers, as well as senior science policy and research developers in Denmark.[5]

Academic career

After being awarded her B.S. degree in Mathematics in 1984, Hau continued to study at the University of Aarhus for her Master's degree in Physics which was awarded two years later. For her doctoral studies in quantum theory Hau worked on ideas similar to those involved in fibre optic cables carrying light, but her work involved strings of atoms in a silicon crystal carrying electrons. While working towards her doctorate Hau spent seven months at CERN, the European Laboratory for Particle Physics near Geneva. She received her doctorate from the University of Aarhus in Denmark in 1991, but by this time her research interests had changed direction. In 1991 she joined the Rowland Institute for Science at Cambridge, Massachusetts as a scientific staff member, beginning to explore the possibilities of slow light and cold atoms. In 1999, Hau accepted a two-year appointment as a postdoctoral fellow at Harvard University. Her formalized training is in theoretical physics but her interest moved to experimental research in an effort to create a new form of matter known as a Bose–Einstein condensate. "Hau applied to the National Science Foundation for funds to make a batch of this condensate but was rejected on the grounds that she was a theorist for whom such experiments would be too difficult to do."[6] Undeterred, she gained alternative funding, and became one of the first handful of physicists to create such a condensate. In September 1999 she was appointed the Gordon Mckay Professor of Applied Physics and Professor of Physics at Harvard.[7] She was also awarded tenure in 1999, and is now Mallinckrodt Professor of Physics and Applied Physics at Harvard. In 2001 she became the first person to stop light completely,[8] using a Bose–Einstein condensate to achieve this. Since then she has produced copious research, and new experimental work, in electromagnetically induced transparency, various areas of quantum physics, photonics and contributed to the development of new quantum devices and novel nanoscale applications.

Qubit transfer

Transfer of light into matter, then back to light using Bose–Einstein Condensates

Hau and her associates at Harvard University "have demonstrated exquisite control over light and matter in several experiments, but her experiment with 2 condensates is one of the most compelling".[9] In 2006 they successfully transferred a qubit from light to a matter wave and back into light, again using Bose–Einstein condensates. Details of the experiment are discussed in the February 8, 2007 publication of the journal Nature.[10] The experiment relies on the way that, according to quantum mechanics, atoms may behave as waves as well as particles. This enables atoms to do some counterintuitive things, such as passing through two openings at once. Within a Bose–Einstein condensate a light pulse is compressed by a factor of 50 million, without losing any of the information stored within it. In this Bose–Einstein condensate, information encoded in a light pulse can be transferred to the atom waves. Because all the atoms move coherently, the information does not dissolve into random noise. The light drives some of the cloud's roughly 1.8 million sodium atoms to enter into "quantum superposition" states, with a lower-energy component that stays put and a higher-energy component that travels between the two clouds. A second 'control' laser then writes the shape of the pulse into the atom waves. When this control beam is turned off and the light pulse disappears, the 'matter copy' remains. Prior to this, researchers could not readily control optical information during its journey, except to amplify the signal to avoid fading. This experiment by Hau and her colleagues marked the first successful manipulation of coherent optical information. The new study is "a beautiful demonstration", says Irina Novikova, a physicist at the College of William and Mary in Williamsburg, VA. Before this result, she says, light storage was measured in milliseconds. "Here it's fractional seconds. It's a really dramatic time."[11]

Of its potential, Hau said "While the matter is traveling between the two Bose–Einstein condensates, we can trap it, potentially for minutes, and reshape it – change it – in whatever way we want. This novel form of quantum control could also have applications in the developing fields of quantum information processing and quantum cryptography."[12] Of the developmental implications, “This feat, the sharing around of quantum information in light-form and in not just one but two atom-forms, offers great encouragement to those who hope to develop quantum computers,” said Jeremy Bloxham, dean of science in the Faculty of Arts and Sciences.[13] Hau was awarded the George Ledlie Prize for this work, Harvard's Provost Steven Hyman noting “her work is path-breaking. Her research blurs the boundaries between basic and applied science, draws on the talent and people of two Schools and several departments, and provides a literally glowing example of how taking daring intellectual risks leads to profound rewards.”[13]

Cold atoms and nanoscale systems

A captured atom is ripped apart as its electron is sucked into the nanotube

In 2009 Hau and team laser-cooled clouds of one million rubidium atoms to just a fraction of a degree above absolute zero. They then launched this millimeter-long atomic cloud towards a suspended carbon nanotube, located some two centimeters away and charged to hundreds of volts. The results were published in 2010, heralding new interactions between cold atoms and nanoscale systems.[14] They observed that most atoms passed by, but approximately 10 per million were inescapably attracted, causing them to dramatically accelerate both movement and temperature. "At this point, the speeding atoms separate into an electron and an ion rotating in parallel around the nanowire, completing each orbit in just a few trillionths of a second. The electron eventually gets sucked into the nanotube via quantum tunneling, causing its companion ion to shoot away – repelled by the strong charge of the 300-volt nanotube – at a speed of roughly 26 kilometers per second, or 59,000 miles per hour."[15] Atoms can rapidly disintegrate, without having to collide with each other in this experiment. The team is quick to note that this effect is not produced by gravity, as calculated in blackholes that exist in space, but by the high electrical charge in the nanotube. The experiment combines nanotechnology with cold atoms to demonstrate a new type of high-resolution, single-atom, chip-integrated detector that may ultimately be able to resolve fringes from the interference of matter waves. The scientists also foresee a range of single-atom, fundamental studies made possible by their setup.[16]

Awards

Publications

Further reading

Absolute Zero and the Conquest of Cold

References

  1. 1 2 "Lene Hau".
  2. ↑ Coherent control of optical information with matter wave dynamics
  3. ↑ "Physics 129. Energy Science | FAS Registrar's Office".
  4. ↑ Keynote speaker Lene Vestergaard Hau
  5. ↑ We need more of investigator-microbe in the blood
  6. ↑ "Hau wins MacArthur".
  7. ↑ "Hau Receives Tenure; Physics Professor Slowed Light".
  8. ↑ Lene Hau
  9. ↑ Physics for the 21st century
  10. ↑ "Turning light into matter:Coherent control of optical information with matter wave dynamics".
  11. ↑ "Trapped in cloud of ultracold atoms, light stayed frozen for 1.5 seconds: technique, if improved, could lead to light-storage devices.".
  12. ↑ "Light Changed to Matter, Then Stopped and Moved".
  13. 1 2 "Hau awarded prestigious Ledlie".
  14. 1 2 "Field Ionization of Cold Atoms near the Wall of a Single Carbon Nanotube".
  15. ↑ "Cold atoms and nanotubes come together in an atomic 'black hole'".
  16. ↑ "Physics – Ionizing atoms with a nanotube".
  17. ↑ "2011 honorary alum: Lene Vestergaard Hau".
  18. ↑ "Hau Lab at Harvard".
  19. ↑ "Videnskabernes Selskab".
  20. ↑ Hans Christian Oersted Lecture, 16 September 2010:Quantum control of light and matter – from the macroscopic to the nanoscale
  21. ↑ "Kvindelig lysgeni er Årets Verdensdansker".
  22. ↑ "Meet the 2010 National Security Science & Engineering Faculty Fellows | Armed with Science".
  23. ↑ "Hau, Lene Vestergaard (Danish scientist)".
  24. ↑ "Lene Hau and condensed matter physics, transcript | AAAS MemberCentral".
  25. ↑ Members List
  26. ↑ "Hau biography".
  27. ↑ Wizardry with Light: Freeze, Teleport, and Go!
  28. ↑ "Rigmor og Carl Holst-Knudsens Videnskabspris".
  29. ↑ "Ledlie Prize for research expected to improve fiber optics and computing".
  30. ↑ "Richtmyer Memorial Lecture".
  31. ↑ The Nano-Lectures: Lene Hau
  32. ↑ Light at Bicycle Speed ...and Slower Yet!
  33. ↑ Hau wins MacArthur
  34. ↑ "128th National Meeting – Featured Speakers".
  35. ↑ "Calendar of Events".
  36. ↑ The year's honorary craftsman (Kjøbenhavns Craftsman Association)
  37. ↑ "Hau Awards".
  38. ↑ "Mobil: Topdanmark".
  39. ↑ "Gordon McKay — Harvard School of Engineering and Applied Sciences".
  40. ↑ "Absolute Zero and the Conquest of Cold".
  41. ↑ Physics – Content by Unit
  42. ↑ "Creation of Long-Term Coherent Optical Memory via Controlled Nonlinear Interactions in Bose–Einstein Condensates".
  43. ↑ "Coherent control of optical information with matter wave dynamics".
  44. ↑ "Observation of Hybrid Soliton Vortex-Ring Structures in Bose–Einstein Condensates".
  45. ↑ Observation of coherent optical information storage in an atomic medium using halted light pulses
  46. ↑ Light speed reduction to 17 metres per second in an ultracold atomic gas
  47. ↑ Quantum Optics: Slowing single photons
  48. ↑ Optical Nanotraps for Neutral Atoms
  49. ↑ "Optical information processing in Bose–Einstein condensates".
  50. ↑ Quantum physics – Tangled memories
  51. ↑ Nonlinear optics: Shocking superfluids
  52. ↑ A High Flux Source of Cold Rubidium
  53. ↑ "Optics & Photonics News – Ultraslow Light & Bose–Einstein Condensates: Two-way Control with Coherent Light & Atom Fields".
  54. ↑ Ultra Low-Power All-Optical Switching
  55. ↑ "Detection and quantized conductance of neutral atoms near a charged carbon nanotube".
  56. ↑ Storing and processing optical information with ultraslow light in Bose–Einstein condensates
  57. ↑ The art of taming light: ultra-slow and stopped light | Europhysics News
  58. ↑ Frozen Light: Scientific American and Special Scientific American Issue entitled "The Edge of Physics" (2003)
  59. ↑ Observation of Quantum Shock Waves Created with Ultra- Compressed Slow Light Pulses in a Bose–Einstein Condensate
  60. ↑ PhysicsWorld Archive » Volume 14 » Taming light with cold atoms
  61. ↑ Observation of interaction dynamics in finite-temperature Bose condensed atom clouds
  62. ↑ "Anisotropic Expansion of Finite Temperature Bose Gases — Emergence of Interaction Effects Between Condensed and Non-Condensed Atoms".
  63. ↑ JILA Workshop on BEC and degenerate Fermi gases
  64. ↑ Hau, February 1999 CTAMOP Workshop
  65. ↑ Near-resonant spatial images of confined Bose–Einstein condensates in a 4-Dee magnetic bottle
  66. ↑ Cold Atoms and Creation of New States of Matter: Bose–Einstein Condensates, Kapitza States, and '2D Magnetic Hydrogen Atoms
  67. ↑ Phys. Rev. Lett. 74, 3138 (1995): Supersymmetry and the Binding of a Magnetic Atom to a Filamentary Current
  68. ↑ A new atomic beam source: The "candlestick"
  69. ↑ Phys. Rev. A 45, 6468 (1992): Bound states of guided matter waves: An atom and a charged wire
  70. ↑ Documentary charting the progress of scientists throughout history who attempted to harness the ultimate limit of cold, known as absolute zero
  71. ↑ Enter the realm of quantum mechanics, where superconductivity and superfluidity and the total absence of magnetism bends our perception of the material world.

External links

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