Determination of long-range interactions from photoassociative spectroscopy of ultracold atoms

1999 ◽  
Author(s):  
William C. Stwalley
Keyword(s):  
Long Range ◽  
Ultracold Atoms ◽  
Long Range Interactions

scholarly journals Engineering long-range interactions between ultracold atoms with light

2022 ◽  
Author(s):  
Ting XIE ◽  
Andrea Orbán ◽  
Xiaodong Xing ◽  
Eliane Luc-Koenig ◽  
Romain Vexiau ◽  
...  
Keyword(s):  
Long Range ◽  
Ultracold Atoms ◽  
Quantum Gases ◽  
Atomic Gases ◽  
Complete Suppression ◽  
Atomic Collisions ◽  
Range Interaction ◽  
Long Range Interactions ◽  
To Come ◽  
A Minor

Abstract Ultracold temperatures in dilute quantum gases opened the way to an exquisite control of matter at the quantum level. Here we focus on the control of ultracold atomic collisions using a laser to engineer their interactions at large interatomic distances. We show that the entrance channel of two colliding ultracold atoms can be coupled to a repulsive collisional channel by the laser light so that the overall interaction between the two atoms becomes repulsive: this prevents them to come close together and to undergo inelastic processes, thus protecting the atomic gases from unwanted losses. We illustrate such an optical shielding mechanism with 39K and 133Cs atoms colliding at ultracold temperature (<1 microkelvin). The process is described in the framework of the dressed-state picture and we then solve the resulting stationary coupled Schrödinger equations. The role of spontaneous emission and photoinduced inelastic scattering is also investigated as possible limitations of the shielding efficiency. We predict an almost complete suppression of inelastic collisions over a broad range of Rabi frequencies and detunings from the 39K D2 line of the optical shielding laser, both within the [0, 200 MHz] interval. We found that the polarization of the shielding laser has a minor influence on this efficiency. This proposal could easily be formulated for other bialkali-metal pairs as their long-range interaction are all very similar to each other.

scholarly journals Combining DNP NMR with segmental and specific labeling to study a yeast prion protein strain that is not parallel in-register

2017 ◽  
Vol 114 (14) ◽  
pp. 3642-3647 ◽  
Author(s):  
Kendra K. Frederick ◽  
Vladimir K. Michaelis ◽  
Marc A. Caporini ◽  
Loren B. Andreas ◽  
Galia T. Debelouchina ◽  
...  
Keyword(s):  
Prion Protein ◽  
Long Range ◽  
Isotopic Labeling ◽  
Yeast Prion ◽  
Long Range Interactions ◽  
Intermolecular Contacts ◽  
Protein Strain ◽  
Segmental Isotopic Labeling ◽  
Chemical Shift Degeneracy

The yeast prion protein Sup35NM is a self-propagating amyloid. Despite intense study, there is no consensus on the organization of monomers within Sup35NM fibrils. Some studies point to a β-helical arrangement, whereas others suggest a parallel in-register organization. Intermolecular contacts are often determined by experiments that probe long-range heteronuclear contacts for fibrils templated from a 1:1 mixture of 13C- and 15N-labeled monomers. However, for Sup35NM, like many large proteins, chemical shift degeneracy limits the usefulness of this approach. Segmental and specific isotopic labeling reduce degeneracy, but experiments to measure long-range interactions are often too insensitive. To limit degeneracy and increase experimental sensitivity, we combined specific and segmental isotopic labeling schemes with dynamic nuclear polarization (DNP) NMR. Using this combination, we examined an amyloid form of Sup35NM that does not have a parallel in-register structure. The combination of a small number of specific labels with DNP NMR enables determination of architectural information about polymeric protein systems.

scholarly journals CASIMIR EFFECT AS A TEST FOR THERMAL CORRECTIONS AND HYPOTHETICAL LONG-RANGE INTERACTIONS

2005 ◽  
Vol 20 (11) ◽  
pp. 2205-2221 ◽  
Author(s):  
G. L. KLIMCHITSKAYA ◽  
R. S. DECCA ◽  
E. FISCHBACH ◽  
D. E. KRAUSE ◽  
D. LÓPEZ ◽  
...  
Keyword(s):  
Long Range ◽  
Casimir Force ◽  
Casimir Effect ◽  
Newtonian Gravity ◽  
Parallel Plates ◽  
Interaction Range ◽  
Rigorous Approach ◽  
Long Range Interactions ◽  
The Standard Model

We have performed a precise experimental determination of the Casimir pressure between two gold-coated parallel plates by means of a micromachined oscillator. In contrast to all previous experiments on the Casimir effect, where a small relative error (varying from 1% to 15%) was achieved only at the shortest separation, our smallest experimental error (~ 0.5%) is achieved over a wide separation range from 170 nm to 300 nm at 95% confidence. We have formulated a rigorous metrological procedure for the comparison of experiment and theory without resorting to the previously used root-mean-square deviation, which has been criticized in the literature. This enables us to discriminate among different competing theories of the thermal Casimir force, and to resolve a thermodynamic puzzle arising from the application of Lifshitz theory to real metals. Our results lead to a more rigorous approach for obtaining constraints on hypothetical long-range interactions predicted by extra-dimensional physics and other extensions of the Standard Model. In particular, the constraints on non-Newtonian gravity are strengthened by up to a factor of 20 in a wide interaction range at 95% confidence.

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