home | index | units | counting | geometry | algebra | trigonometry & functions | calculus
analysis | sets & logic | number theory | recreational | misc | nomenclature & history | physics

Final Answers
© 2000-2016   Gérard P. Michon, Ph.D.

Haroche Experiment
Nondestructive Counting of Photons

 border  border

Related articles on this site:

Serge Haroche.  French physicist born in 1944 in Casablanca.  In 1963, he ranked first at the Polytechnique entrance exam and third at ENS, which he chose to enter.  In 1971, he earned a doctorate under Cohen-Tannoudji.  From 1974 to 1984, Haroche taught Quantum Mechanics at Polytechnique  (the author was a student of his, in the Fall of 1977).  Serge Haroche held the chair of Quantum Mechanics at the  Collège de France  from 2001 to 2015.

Britannica ]       Aimé Cotton prize (1971).
Michelson Award (1993) from the Franklin Institute.
CNRS Gold Medal (2009)   |   Nobel Prize (Physics, 2012)

 Serge Haroche

Related Links (Outside this Site)

Cavity Quantum Electrodynamics  by  S. Haroche  and  D. Kleppner  (1989).
Cavity QED  S. Haroche, J-M Raimond  (Scientific American, April 1993).
Death of a Photon...  Live   by  Claire Le Poulennec   (CNRS, July 2007).
Serge Haroche: Photon Tamer (2009 CNRS Gold Medal)  by  Emilie Badin.
Serge Haroche on Quantum Optics.  Interview by  Emmanuelle Manck   (2009).
Quantum Computing Wins a Nobel  by  Joshua Rothman  (2012-10-12).
The secrets of my prizewinning research  by S. Haroche  (Nature, 2012-10-17).
Transcript of Serge Haroche's Nobel lecture   (Rev. Mod. Phys. 85, 1083).
Haroche CV   |   Cavity QED  at  Laboratoire Kastler Brossel (ENS).
Exceptional Conference in Mulhouse  by  Serge Haroche  (EPS, June 2016).
Serge Haroche (b.1944; ENS 1963)  |  Jean-Michel Raimond (b.1955; ENS 1975)  |  Michel Brune (ENS 1983)
Wikipedia :   Cavity QED   |   Quantum optics   |   Quantum information

ISBN 0-19-850914-6   Exploring the Quantum:  Atoms, Cavities and Photons
by Serge Haroche and Jean-Michel Raimond  (Oxford Graduate Texts, 2006).

Videos :   Serge Haroche, un arpenteur du monde quantique   (2009).
Official Presentation of the 2012 Nobel Prize in Physics  (2012-10-09).
Announcement of the Nobel Prize in Physics  by  Brady Haran  (2012-10-09).
How do we see lightMinute Physics  by  Henry Reich  (2012-10-09).
Serge Haroche, Prix Nobel de physique 2012  (France-Inter, 2012-10-11).
L'étrangeté quantique:  Serge Haroche  (Collège de France, Dec. 2012).
Nobel Lecture by Serge Haroche  (2012-12-08).
Nobel Lecture at Uppsala University  (2012-12-13).
Conférence de Serge Haroche à l'Ecole Polytechnique   (2014-03-27).
Shedding new light on Schrödinger's cat  (Schrödinger Lecture 2014, ICL).
Le chat de Schrödinger sous un nouvel éclairage.  (ESPCI, 2015-01-15).
Light and the Quantum:  Opening ceremony, 2015 International Year of Light.
Chats de Schrödinger et décohérenceJean-Michel Raimond  (2015-01-29).
Contrôle non-destructif de photons en cavitéSerge Haroche  (2015-01-29).
Septième Tables Rondes de l'Arbois  (Aix-en-Provence, March 2015).
Light and the Quantum  Serge Haroche  (The Royal Institution, Nov. 2015).

 International Year of Light 2015
Year of Light
Light-Based Technologies
 International Year of Light

Counting Photons without Destroying Them
A review of the components of the Haroche experiment at ENS.

(2015-08-30)   Weighing a Box of Photons  (1930 thought experiment)
A quantum paradox devised by  Einstein  and solved by  Niels Bohr.

In 1930, Einstein proposed a thought-experiment which seemed to refute the  uncertainty principle applied to time and energy.  The very foundations of  Quantum Theory were threatened...

 Bohr-Einstein photon box At left is Bohr's own depiction of the apparatus that the Einstein experiment would involve.  The box is supposed to trap photons indefinitely with perfectly reflective walls.

Einstein argued that a shutter can be opened for an arbitrarily small amount of time  Dmeasured  by the attached clock.

As the energy of the closed box can be determined with arbitrary precision by weighing it over long periods of time,  so can the difference  DE  corresponding to light released at a time  t  known with the aforementioned arbitrarily small precision  Dt.

DE   =   ( M0 - M1 ) c 2

After a sleepless night, Bohr discovered the fallacy in Einstein's argument using, ironically, Einstein's own  General Theory of Relativity:

 Come back later, we're
 still working on this one...

Wikipedia :   Bohr-Einstein debates

(2015-09-06)   Purcell Effect

The  Purcell effect  is the enhancement of the  spontaneous emission rate  of fluorescent atoms in a resonant cavity.

 Come back later, we're
 still working on this one...

Wikipedia :   Purcell effect   |   Edward Mills Purcell (1912-1997; Nobel 1952)

(2015-09-06)   Quantum Non-Demolition  (QND)  Measurement

 Come back later, we're
 still working on this one...

Quantum nondemolition measurement   |   Vladimir Borisovitch Braginsky (b. 1931)

(2015-08-28)   Circular Rydberg Atoms  [of Rubidium]
Excited atoms whose outermost electron orbits at a large distance.

Rydberg atom  is a neutral atom whose outermost electron has a very high principal quantum number  (n).  The Haroche group used primarily rubidium atoms with n=50 and n=51.

Circular Rydberg atoms  are Rydberg atoms whose outer electrons have maximal  orbital  (l)  and  magnetic  (m)  quantum numbers.

 Come back later, we're
 still working on this one...

Atoms in Circular States (CQED)   |   Dan Kleppner (b. 1932)   |   Randy Hulet (b. 1956)
Wikipedia :   Rydberg atom

(2015-08-30)   Rydberg Clock   (0.1 ppm  accuracy)
Quantum superposition  of two states  (n=50 & n=51)  of a Rydberg atom.

The superposition of two adjacent circular Rydberg states  |g>  (n=50)  and  |e>  (n=51)  looks like a rotating  electric dipole.

For rubidium,  the transition between  |e>  and  |g>  corresponds to a microwave frequency of  51.099 GHz  (5.8669 mm wavelength).

 Come back later, we're
 still working on this one...

(2015-08-30)   Fabry-Pérot Cavity
Polarized open cavity.

 Come back later, we're
 still working on this one...

Fabry-Pérot interferometer   |   Charles Fabry (1867-1945; X1885)   |   Alfred Pérot (1863-1925; X1882)
Gires-Tournois interferometer (1964)   |   François Gires (1931-2013)   |   Pierre Tournois (1936-)

(2015-09-05)   Superconductivity of Niobium  (Nb)
Photons bounce 0.13 s between two copper mirrors coated with niobium.

The name  Niobium  has been officially adopted internationally since 1949,  but the former American name of  Columbium  (Cb)  is still used by some metallurgists.  The antiquated name also survives in publications from the  US Geological Survey.

 Come back later, we're
 still working on this one...

Chemical elements   |   Niobium   |   Superconductivity

(2015-08-31)   Fock States and Fock Base
Quantum states corresponding to a well-defined number of particles.

Vladimir Aleksandrovich Fock  (1898-1974)  derived the  Klein-Gordon equation in 1926.

 Come back later, we're
 still working on this one...

Fock state   |   Fock space   |   Vladimir A. Fock (1898-1974)

(2015-08-31)   Phase of the Electromagnetic Field
Conjugate quantity  of the number of photons.

 Come back later, we're
 still working on this one...

Fock state   |   Fock space   |   Vladimir A. Fock (1898-1974)

(2015-11-12)   Coherent States   (Roy J. Glauber, 1963)
States with a well-defined amplitude and phase.

 Come back later, we're
 still working on this one...

Wikipedia :   Coherent states   |   Roy Jay Glauber (1925-, Nobel 2005)

(2015-08-30)   Light-Shift Effect   (Claude Cohen-Tannoudji, 1961)

 Come back later, we're
 still working on this one...

"Culture Physiques" (videos hosted by Etienne Klein) :  Qu'est-ce-que la lumière?   1  |  2  |  3  |  4
Claude Cohen-Tannoudji (b. 1933; ENS 1953; Nobel 1997)

(2015-09-05)   Rabi Oscillations at  50 kHz
Damped oscillations of an excited atom in an electromagnetic resonator.

I.I. Rabi (1898-1988; Nobel 1944) was head of the wartime  Radiation Laboratory  at MIT.  He discovered nuclear magnetic resonance (NMR) in molecular beams.

|i> n=49

 Come back later, we're
 still working on this one...

Wikipedia :   Rabi flop   |   Vacuum Rabi oscillation   |   Rabi frequency

(2015-08-30)   Ramsey Interferometer   (Norman Ramsey, 1949)
The separated oscillatory field method.

Norman Ramsey  (1922-1993; Nobel 1989) earned his doctorate at Columbia under Rabi.  He was himself the doctoral advisor of  David J. Wineland, who shared the Nobel Prize for physics with  Serge Haroche  in 2012.

 Come back later, we're
 still working on this one...

Wikipedia :   Ramsey interferometer   |   Norman Ramsey (1922-1993; Nobel 1989)

visits since September 9, 2015
 (c) Copyright 2000-2016, Gerard P. Michon, Ph.D.