1. The document discusses the formation of squeezed quantum states in Bose-Einstein condensates trapped in optical lattices. By slowly ramping up the depth of the optical lattice, the atoms can be prepared in a number-squeezed state.
2. Releasing the atoms from the lattice allows their wavefunctions to overlap and interfere, providing a way to probe the quantum phase state of the atoms. Number-squeezed states are observed to produce interference patterns with higher contrast than coherent states.
3. Variational calculations of the quantum state dynamics during lattice ramping and dephasing agree qualitatively with experimental observations of the transition between coherent and squeezed states.
This PPT contains all about cyclotron. That is introduction, history, types, uses, construction, working and limitations of cyclotron. This PPT also contains derivation and formula for cyclotron. Pictorial presentation is understandable for higher secondary school student. Although it is for Bachelor's level.
This PPT contains all about cyclotron. That is introduction, history, types, uses, construction, working and limitations of cyclotron. This PPT also contains derivation and formula for cyclotron. Pictorial presentation is understandable for higher secondary school student. Although it is for Bachelor's level.
Ion implantation is used in semiconductor device fabrication and in metal finishing, as well as in material science research.
it is a low temperature process that includes the acceleration of ions of a particular element towards a target, altering the chemical and physical properties of the target.
cyclotron that accelerate the charge particles prior their bombardment to the target nuclei.
it is developed by E.O.Lawrence & he was awarded by nobel prize in this work. it accelerate the particle from 1MeV to the more than 100 MeV.
it contains the electric & magnetic system to accelerate the charge particles.
electric field acts horizontally & magnetic field act vertically.
particle moves in spiral path and its energy , radius & velocity increases.
after that it moves out of window ( diflactor plate) n hit the target.
n then the nuclear reaction starts.
it is used to treat cancer.
produce positrons emission isotopes for PET imaging.
it do not accelerate the neutrons, electrons & positive charge with higher mass.
Ion implantation is used in semiconductor device fabrication and in metal finishing, as well as in material science research.
it is a low temperature process that includes the acceleration of ions of a particular element towards a target, altering the chemical and physical properties of the target.
cyclotron that accelerate the charge particles prior their bombardment to the target nuclei.
it is developed by E.O.Lawrence & he was awarded by nobel prize in this work. it accelerate the particle from 1MeV to the more than 100 MeV.
it contains the electric & magnetic system to accelerate the charge particles.
electric field acts horizontally & magnetic field act vertically.
particle moves in spiral path and its energy , radius & velocity increases.
after that it moves out of window ( diflactor plate) n hit the target.
n then the nuclear reaction starts.
it is used to treat cancer.
produce positrons emission isotopes for PET imaging.
it do not accelerate the neutrons, electrons & positive charge with higher mass.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
The Exotic Physics of an Ordinary MorningChad Orzel
Slides from my TEDxAlbany talk, December 3, 2015. The topic was showing the was that quantum-mechanical phenomena show up in mundane morning activities like making toast, waking to an alarm, and checking social media.
Talking Dogs and Galileian Blogs: Social Media for Communicating ScienceChad Orzel
Slides from my Forman Lecture talk at Vanderbilt University 3/26/15. Arguing that the current state of the world demands greater engagement with a broader public on the part of scientists, and that social media can be a powerful tool for this. Including discussion of pros and cons of specific platforms, and advice based on 12+ years of talking science on the Internet, sometimes with my dog.
High Precision, Not High Energy: Using Atomic Physics to Look Beyond the Stan...Chad Orzel
Second of two lectures on using atomic physics techniques to look for exotic physics, given at the Nordita Workshop for Science Writers on Quantum Theory. This one focusses on the measuring of tiny frequency shifts using techniques developed for atomic clocks.
Talk for the Bristol (UK) Festival of Ideas on similarities between everyday activities like crosswords, card games, and sports and the process of scientific discovery.
Slides for a talk given at Physics Day at Space Center Houston, May 1-2 2014. Explains why nothing can move faster than the speed of light using spacetime diagrams.
Lecture slides for a class giving a historical overview of quantum mechanics, including black-body radiation, the photoelectric effect, and the Bohr model of hydrogen. Used in a class for non-majors titled "A Brief History of Timekeeping," as a lead-in to talking about atomic clocks.
Lecture slides from a class on atomic clocks, giving an overview of the basic idea and some of the history leading up to modern laser-cooled cesium fountain clocks. Given as part of a class for non-majors titled "A Brief History of Timekeeping."
Lecture slides from a class introducing quantum mechanics to non-majors, giving an overview of black-body radiation, the photoelectric effect, and the Bohr model. Used as part of a course titled "A Brief history of Timekeeping," as a lead-in to talking about atomic clocks
What's So Interesting About AMO Phyiscs?Chad Orzel
A talk given at the 2011 meeting of the Division of Atomic, Molecular, and Optical Physics (DAMOP) of the American Physical Society, summarizing recent and exciting results in AMO physics being presented at the meeting.
What Every Dog Should Know About Quantum PhysicsChad Orzel
A public lecture on quantum physics and why it is important enough that even dogs should know about it. Based on my book, ow to Teach Physics to Your Dog. Given at the University of Alabama on 9/30/10.
What Every Dog Should Know About Quantum PhysicsChad Orzel
A talk on the essential elements of quantum mechanics, given to a group of Albany area home-schooled students and parents. The second slide is a video of a dramatic reading of Chapter 3 of _How to Teach Physics to Your Dog_ (Scribner, 2009, available wherever books are sold); the video can be found on YouTube.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
Overview on Edible Vaccine: Pros & Cons with Mechanism
"Squeezed States in Bose-Einstein Condensate"
1. Ari Tuchman Matt Fenselau Mark Kasevich Squeezed States in a Bose-Einstein Condensate Yale University Brian Anderson (JILA) Masami Yasuda (Tokyo) Chad Orzel $$ - NSF, ONR (Now at Union College)
2. Bose-Einstein Condensate 2001 NOBEL PRIZE in PHYSICS Eric Cornell Carl Wieman Wolfgang Ketterle “ For the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates".
3. Uncertainty Principle x p / 2 Best known form: Fundamental limit on knowledge Improve measurement of position Lose information about momentum Position - Momentum Uncertainty x 0 p Important on microscopic scale ~ 10 -34 Minimum Uncertainty Wavepacket x p = / 2 p = / 2 x x h h h h
4. Uncertainty and Light Light Wave: Uncertainty: E t / 2 Energy- Time Uncertainty Energy: Amplitude of wave Time: Phase of wave h
5. Squeezed States N N Number-phase uncertainty N 1/2 Coherent State: Minimum Uncertainty State N = 1/2 Squeezed State: Smaller N Larger Still N = 1/2 Studied with light -> Do same thing with atoms N
6. Michelson Interferometer Laser Beam Splitter Mirror L Light from two arms overlaps, interferes Can measure changes in path length difference ( L) Can measure phase shifts ( ) Detector
8. Interference of Molecules M. Arndt et al., Nature 401, 680-682, 14.October 1999 Source Grating Detector
9. Atom Interferometry N 1 N 2 General Scheme: Detectors for Rotation, Acceleration, Gravity Gradients, etc. Beam splitters/ gratings Atom Beam Improve by using Squeezed States?
10. Bose-Einstein Condensation High Temperature Like classical particles BEC Low Temp. Quantum wavepackets T < T c First Rb BEC, JILA, 1995
11. Interfering BEC (Ketterle group, MIT) Two BEC's created in trap Let fall, overlap, interfere Fringes in overlap region M.R. Andrews et al ., Science 275, 637 (1997)
12. Path to BEC Laser Cooling Cool atoms to ~ 100 K Trap ~ 10 8 - 10 9 Atoms Room Temperature Rb vapor cell Magnetic Trap (TOP) Evaporative Cooling Remove hot atoms from trap Remaining Atoms get colder BEC ~ 30,000 atoms T < 100nK
13. Absorptive Imaging CCD Illuminate sample with collimated laser Atoms absorb light => Image “shadow” on camera BEC Probe Only Subtracted Image 50 m BEC
14. Optical Lattice Laser shifts energy levels Lower energy of ground state |g> |e> Standing Wave Periodic Potential Atoms trapped in high intensity
15. Optical Lattice U o 1-D Optical Lattice 840 nm ( = 60 nm) Focus to 60 m, retro-reflect <0.04 photons/sec Neglect scattering Atoms localized at anti-nodes of standing wave Array of traps spaced by /2 BEC
16. Atomic Tunnel Array Output Array Output: Measured pulse period of ~1.1 msec is in excellent agreement with calculated J = mg z/ ( z= / 2) .
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19. Double-Well Potential Tunneling : Atoms hop between wells Tunneling Energy: Mean Field Interaction: Collisions between atoms in same well Collision Energy: Ng Ratio Ng / Determines Character of Ground State H = (a L + a R + a R + a L ) + g (N L 2 + N R 2 )
20. Ground states Assume | = c n |n, N-n Left trap Right trap Ng non-interacting) | = { (a L + + a R + )/ 2} N | vac Ng For Ng | = { a L + } N/2 { a R + } N/2 | vac Note: Squeezed solutions can not be obtained with Gross-Pitaevskii Eq., which assumes a coherent state and large N. Squeezed
21. Lattice potential Use variational method to find ground-state: Example solution: “ Soft” Bose-Hubbard model 30 lattice sites Ng ~50 atoms/site (center) Lattice plus harmonic potential Vary n 0 , Ansatz, | = | i ( i indexes lattice site) where, | i ~ exp -{(n-n 0 ) 2/ } |n
23. Quantum Optics and BEC Coherent state: Undefined phase, fixed amplitude Number-phase uncertainty N 1/2 (from Loudon, Quant. Theory of Light) Recent work by Javanainen, Castin and Dalibard, 1996 State of system when tunneling fast, interactions weak State when mean-field large, tunneling slow Fock state:
24. Tunnel Array as Phase Probe ~12 wells occupied Release atoms from lattice Atom clouds expand, overlap, interfere Like multiple-slit diffraction Coherent State: Well-defined phase Sharp interference Fock State: Large phase variance Interference washes out Atoms held in lattice
25. Squeezed State Formation (a) (b) (c) (d) (e) (f) 8 E r 18 E r 44 E r ramp = 200 msec Lattice strength Harmonic trap off Density image
28. Simple Theory Comparison Convert B ’ q , U o to Ng Compare to model to extract phase variance 2 = S o 2 ~ S (1/N) Fit (Ng / ) C Theory: C = ½ Fit: C = 0.54(9) 0 10 20
29. Fock Coherent 200 ms 150 ms 44 E r 11 E r 13 E r 41 E r 44 -> 11 E r Adiabatically ramp up to make squeezed state Ramp down to return to coherent state Non-Adiabatic (2ms ramp up, 10ms dephasing):
30. Quantum state dynamics Adiabatically ramp lattice depth to prepare number squeezed states Suddenly drop lattice depth to allow tunneling (Drop slow compared to vibration frequency in well) Time dependent variational estimate for phase variance per lattice well Experimental signature: breathing in interference contrast Number squeezed state Time Variance time Lattice depth
32. Conclusion Can make number-squeezed states with a BEC in an optical lattice Use interference of atoms to probe phase state Observed factor of ~30 reduction in N N= 2500 ± 50 2500 ± 2 Future: Look at transition between coherent/ squeezed Quantum State Dynamics Ultimate Goal: Squeezed State Atom Interferometry Have Shown: Quantum Phase Transition
35. Dephasing Mechanisms 1) Ensemble phase dispersion (inhomogeneous broadening) 2) Coherent-state (self) phase dispersion 3) Squeezing Mean number (thus phase) varies trap-to-trap. Mean-field interaction + initial number variance phase dispersion at each trap control parameter Trap i External control parameter used to control quantum many-body state at each trap Trap 2 Trap N ··· (Phasor diagrams) Trap 1 n Trap i Trap i time evolution Trap i
36. Inhomogeneous Phase Broadening 2ms Hold t Ramp up in 2ms, hold for variable time Wells evolve independently ~23 E r Dephasing Time ~ (B q ) -2 => Harmonic trap
40. BEC Apparatus 87 Rb F = 2 m = 2 state Single Vapor Cell MOT ~ 10 4 atoms in condensate TOP and RF evaporation 1-D Optical Lattice 850 nm ( = 70 nm) Focus to 60 m Absorptive Imaging
41. Double-well system Left trap Right trap H = (a L + a R + a R + a L ) - g a L + a L a R + a R Hamiltonian tunneling mean field Literature A. Imamoglu, M. Lewenstein, and L. You, PRL 78 2511 (1997). R. Spekkens and J. Sipe, PRA 59 , 3868 (1999). A. Smerzi and S. Raghavan, cond-mat/9905059. J. Javanainen, preprint, 1998. What is the many-body ground state of this system (assume N atoms are partitioned between the two traps)? Adiabatically manipulate tunnel barrier height
42. Hold and Release 200 msec ramp 200 msec ramp + 100 msec hold 200 msec ramp + 500 msec hold ramp hold Lattice strength Harmonic trap off ~6 E r depth Density image High atomic density
44. Time-dependent Variational Calculation Wavefunction parameterized in terms of mean and variance of atom number and phase for each lattice site: Model allows for calculation of time evolution of quantum state. Valid for < 1 rad. ~ ( Tunneling energy / mean field energy ) Time dependent equations for variational parameters: where Lattice wavefunction:
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46. Squeezed States N N Number-phase uncertainty N 1/2 Coherent State: Minimum Uncertainty State N = 1/2 Squeezed State: Smaller N Larger Still N = 1/2 Studied with light -> Do same thing with atoms N
47. TOP Trap Quadrupole Trap B ~ B ' q x Tightly confining, but spin-flip losses Apply rotating bias field ~ 10 kHz Time-averaged potential Harmonic: U ~ B ' q 2 B rot Circle of Death (Time Orbiting Potential)
48. Evaporative Cooling Remove hot atoms from trap => Remaining sample gets colder TOP Evaporation Reduce rotating field Circle of Death moves in Forced RF Evaporation Drive transition to un-trapped state