We derived the equation in broad resonance approximation and discussed the asymptotic solutions. When a single photon is bounded inside the closed channel by setting the relevant physical parameters appropriately, the vanishing transmission appears to display this photonic feshbach resonance. Feshbach resonances allow us to tune the scattering length atoms over a huge variety of values even allowing us to change the sign as well. Creation and manipulation of feshbach resonances with. Analternativetechniquefor tuning interatomic interactions is optical feshbach resonance ofr 2,3, in which free atom pairs are coupled to an. This enables a to be continuously tuned from positive to negative values. Surko, chairman leonid butov robert continetti charles perrin lu sham. Pdf feshbach resonances in fermionic lithium6 carl. Molecular production at broad feshbach resonance in cold. Here, we will use an even simpler model of a feshbach resonance, in which there is only one. Illustration of the feshbach resonance in a twochannel system. Although feshbach molecules themselves are extremely \fragile, feshbach resonance association is a potentially coherent method that creates molecules in a sin. Cold fermions, feshbach resonance, and molecular condensates ii.
Phase protection of fanofeshbach resonances nature. If the relative kinetic energy of the input particle is. Feshbach is best known for feshbach resonance and for writing, with philip m. Near the broad feshbach resonance, the spontaneous lifetime of the atoms is increased from 0. A feshbach resonance occurs when the energy of two interacting free particles comes into resonance with a molecular bound state. Scattering resonances known as feshbach resonances occur when the collision energy of two free atoms coin. A feshbach resonance is a collisional resonance between pairs of free atoms and a bound state of the diatomic molecule, for which differences between the atomic and molecular magnetic moments enable the resonance to be magnetically tuned 1. When approaching this resonance, marked changes in the interaction. This tunability arises from the coupling of free unbound atoms to a molecular state in. How can one physically understand this phenomenon of feshbach resonance.
Here we outline the basic ideas, referring the reader to sec. Read interactive resonance publications at fliphtml5, download resonance pdf documents for free. In addition to two previously known swave resonances, we found three pwave resonances. Optical control of a magnetic feshbach resonance in an. Pdf shifts and widths of feshbach resonances in atomic. Such a shape resonance occurs when the interatomic potential has a bound state that is very weakly bound and, therefore, has an energy that lies very close to the continuum threshold of the atoms. Control of feshbach resonant interactions in ultracold. Feshbach resonances i harishchandra research institute. Bright matter wave solitons in boseeinstein condensates.
Indeed, examples can be found where onedimensional feshbach resonances play an important role. A the pes is very deep, and thus a large number of channels that are asymptotically closed can support the triatomic bound states, which give rise to a high density of resonant states near the threshold. Feshbach resonances in lithium6 were experimentally studied and theoretically analyzed. Pdf a feshbach resonance occurs when the energy of two interacting free particles comes to resonance with a molecular bound state. For each, we consider the extent of control that is possible, the rf. Molecular production strongly depends on the initial value of magnetic field. We implement the open and the closed channels inside a pair of such arrays, linked by a separated cavity or a tunable qubit. Coefficient in the lz exponent for the molecular and the bcs. I think the answer for this question has been already written by me. Feshbach resonance in action by martin zwierlein phd 06 feshbach resonances are a unique tool for the study of ultracold atoms. Four of these resonances are narrow and yield a precise value of the. Molecules can be formed near a feshbach resonance and have recently.
Feshbach resonance ting xie, gaoren wang, yin huang et al. Landauzener transitions and a feshbach resonance in. We consider two molecular potential curves v bgr and v cr, as illustrated in. Realizing analogues of color superconductivity with ultracold alkali atoms k m ohararecent citations. Optical control of magnetic feshbach resonances by closed.
A virtual state, or unstable state is a bound or transient state which can decay into a free state or relax at some finite rate. The two potential curves show the open and closed channel potential curves as a function of the interatomic separation. Their physical mechanisms are different and, following the paradigm set by that historic experiment, it has become customary to refer to the two types of resonance, both common in atomic and molecular physics, as feshbach and shape resonance. Basic physics of a feshbach resonance the physical origin and the elementary properties of a feshbach resonance can be understood from a simple picture. Professor david hall may 8, 2008 submitted to the department of physics of amherst college in partial ful. I will be simplistic in this explanation and will provide specific references at the end of the answer. A 57, 1497 1998 this plot shows the swave scattering length as a function of magnetic field for the two lowest hyperfine groundstates of 6li. Figure 1a shows a simplified twochannel illustration for the origin of the triplet structure. Feshbach resonance and can be varied over a wide range. Landauzener transitions and a feshbach resonance in spinor bose einstein condensates michael lurie goldman advisor. Resonance magazines, resonance ebooks, resonance publications, resonance publishers description.
The spinspin interaction between the valence electrons perturbs the fig. Good insight into the feshbach resonance mechanism can be gained by considering two coupled spherical well potentials, one each for the open and closed channel 262. By the simple change of a magnetic field, the interactions between atoms can be controlled over an enormous range. This state may be the metastable state of a certain class of feshbach resonance, a special case of a feshbachtype resonance occurs when the energy level lies near the very top of the potential well. We directly detect these weakly bound molecules through rf photodissociation spectra that probe the molecular wavefunction and yield binding energies that are consistent with theory. A copy of the license is included in the section entitled gnu free documentation license. Feshbach resonance, bound state, singlephoton transistor pacs. Feshbach resonances are transiently trapped states along a reaction coordinate, providing a probe to the reactions potential energy surface pes but difficult to analyze in polyatomic systems. Feshbach resonances a shape resonance is trapped by a potential barrier. Feshbach resonances in ultracold atoms the budker group. Universal dynamics of a strongly interacting fermi gas.
They have found manifold experimental applications, opening up the way to important breakthroughs. One narrow resonance occurs just below the threshold of that excitation, whereas the second, broad one occurs just above. Vibrational feshbach resonances and positronmolecule bound states a dissertation submitted in partial satisfaction of the requirements for the degree of doctor of philosophy in physics by jason asher young committee in charge. Still you can visit this link scribd read books, audiobooks, and more for such notes. Observation of broad dwave feshbach resonances with a. The trapinduced resonance is basically caused by a shift of the free space feshbach resonance point by the con. Free resonance magazines, ebooks read, download and. They have found numerous experimental applications, opening up the way to important breakthroughs. Herman feshbach february 2, 1917, in new york city 22 december 2000, in cambridge, massachusetts was an american physicist. Per turbatiofl theory for resonances of the feshbach type 915 the effect of the step functions in 2. Where can i download bansal, resonance, and allen material. However, similar threedimensional examples exist in the lit. Two feshbach resonances are shown, a narrow resonance at approximately 550g and a very broad resonance centered near 850 g. Feshbach resonances are the essential tool to control the interaction between atoms in ultracold quantum gases.
Perturbation theory for resonances of the 2 feshbach type. The first is that for energies away from the resonance, 0. A feshbach resonance is a scattering resonance in which pairs of free atoms are tuned via the zeeman effect into resonance with a vibrational state of the diatomicmolecule 16. Consider an example where spinup and spindown states in a system of ultracold fermions can be represented by two zeeman. Feshbach resonance is shifted by 30 times its width and atom loss suppressed by destructive quantum interference. He was an institute professor emeritus of physics at mit.
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