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.

Statistical theory of adsorption with long-range interaction

1938 ◽  
Vol 34 (2) ◽  
pp. 238-252 ◽  
Author(s):  
J. S. Wang
Keyword(s):  
Statistical Theory ◽  
Long Range ◽  
Unit Area ◽  
Continuous Distribution ◽  
Lattice Points ◽  
Circular Region ◽  
Range Interaction ◽  
Dipole Interactions ◽  
Long Range Interactions ◽  
Long Range Interaction

The statistical theory of long-range interactions between adsorbed particles on a plane lattice is worked out approximately, by treating in detail the distribution of adsorbed particles among a few sites inside and on the boundary of a circular region, and regarding the distribution outside the circle as uniform and continuous with a density Kθ per unit area, where K is the number of lattice points per unit area and θ is the fraction of surface covered by adsorbed particles. The continuous distribution begins at a distance ρ from the centre of the circle, ρ being determined by the condition that the probability of occupation of a first shell site is equal to the probability θ of occupation of the central site. Using this method, general formulae for the adsorption isotherm and the heat of adsorption are obtained. Numerical applications for dipole interactions and for quadratic and hexagonal lattices are worked out in detail and the case in which the dipole moment varies with θ is discussed.

LONG-RANGE INTERACTIONS IN THE HELICOIDAL DNA DYNAMICS

2013 ◽  
Vol 27 (24) ◽  
pp. 1350143 ◽  
Author(s):  
MIRABEAU SAHA ◽  
TIMOLEON C. KOFANÉ
Keyword(s):  
Rna Polymerase ◽  
Long Range ◽  
Power Law ◽  
Dna Dynamics ◽  
Extended Version ◽  
Range Interaction ◽  
Dna Molecule ◽  
Long Range Interactions ◽  
Long Range Interaction

In this paper, the comparison between power-law long-range interaction and Kac–Baker long-range interaction in the DNA molecule is investigated. This is done by employing an extended version of spin-like model of the DNA molecule with long-range interaction between intra-strand nucleotides and helicoidal coupling between inter-strand nucleotides when an RNA-polymerase binds to the DNA at biological temperature. Results show that LRIs have an undeniable effect on the DNA dynamics and that one is free to use either PLLRI or KBLRI to study DNA behaviors.

Single-mutation-induced stability loss in protein lysozyme

2007 ◽  
Vol 35 (6) ◽  
pp. 1551-1557 ◽  
Author(s):  
L. Ye ◽  
Z. Wu ◽  
M. Eleftheriou ◽  
R. Zhou
Keyword(s):  
Molecular Mechanism ◽  
Long Range ◽  
Large Scale ◽  
Stability Loss ◽  
Single Mutation ◽  
Wild Type ◽  
Range Interaction ◽  
Local Cluster ◽  
Long Range Interactions ◽  
Arginine Residues

Recent NMR experiments have revealed that a single residue mutation W62G on protein hen's-egg white lysozyme can cause a dramatic loss of long-range interactions and protein stability; however, the molecular mechanism for this surprising phenomenon is not completely clear. In this mini-review, we have summarized some of our recent work on the molecular mechanism with large-scale molecular modelling, and also utilized a new wavelet method to analyse the local structural clusters present in both the wild-type and mutant folding trajectories. These extensive MD (Molecular Dynamics) simulations (10+ μs) were performed in 8 M urea, mimicking the experimental condition. Detailed analyses revealed that the Trp62 residue is the key to a co-operative long-range interaction within the wild-type protein: it acts as a bridge between neighbouring basic residues, mainly arginine residues, through π-type hydrogen bonds or π-cation interactions to form an Arg-Trp-Arg ‘sandwich-like’ local structure. The local cluster near Trp62 further extends its interaction to other clusters, such as the one near Trp111, through Arg112, which is involved in such an Arg-Trp-Arg bridging structure, thus achieving the long-range interactions for the wild-type. On the other hand, the mutant does not have this bridging effect and forms much less local clusters or contacts, and therefore results in a much less stable structure. Overall, these findings not only support the general conclusions of the experiment, but also provide a detailed but somewhat different molecular picture of the disruption of the long-range interactions.

Responding to Media Inquiries about Earthquake Triggering Interactions

2021 ◽  
Author(s):  
Fang Fan ◽  
Lingling Ye ◽  
Hiroo Kanamori ◽  
Thorne Lay
Keyword(s):  
Long Range ◽  
Aftershock Sequence ◽  
Public Understanding ◽  
Physical Interaction ◽  
Earthquake Triggering ◽  
Dynamic Triggering ◽  
Long Range Interactions ◽  
The Media ◽  
To Come ◽  
Frequency Relationship

Abstract In the aftermath of a significant earthquake, seismologists are frequently asked questions by the media and public regarding possible interactions with recent prior events, including events at great distances away, along with prospects of larger events yet to come, both locally and remotely. For regions with substantial earthquake catalogs that provide information on the regional Gutenberg–Richter magnitude–frequency relationship, Omori temporal aftershock statistical behavior, and aftershock productivity parameters, probabilistic responses can be provided for likelihood of nearby future events of larger magnitude, as well as expected behavior of the overall aftershock sequence. However, such procedures generally involve uncertain extrapolations of parameterized equations to infrequent large events and do not provide answers to inquiries about long-range interactions, either retrospectively for interaction with prior remote large events or prospectively for interaction with future remote large events. Dynamic triggering that may be involved in such long-range interactions occurs, often with significant temporal delay, but is not well understood, making it difficult to respond to related inquiries. One approach to addressing such inquiries is to provide retrospective or prospective occurrence histories for large earthquakes based on global catalogs; while not providing quantitative understanding of any physical interaction, experience-based guidance on the (typically very low) chances of causal interactions can inform public understanding of likelihood of specific scenarios they are commonly very interested in.

Responding to Media Inquiries About Remote Triggering Interactions

2020 ◽  
Author(s):  
Lingling Ye ◽  
Hiroo Kanamori ◽  
Thorne Lay
Keyword(s):  
Long Range ◽  
Aftershock Sequence ◽  
Public Understanding ◽  
Physical Interaction ◽  
Dynamic Triggering ◽  
Long Range Interactions ◽  
Future Events ◽  
The Media ◽  
To Come ◽  
Frequency Relationship

&lt;p&gt;In the aftermath of a significant earthquake, seismologists are frequently asked questions by the media and public regarding possible interactions with recent prior events, including events at great distances away, along with prospects of larger events yet to come, both locally or remotely.&amp;#160; For regions with substantial earthquake catalogs that provide information on the regional Gutenberg-Richter magnitude-frequency relationship, Omori temporal aftershock statistical behavior, and aftershock productivity parameters, probabilistic responses can be provided for likelihood of nearby future events of larger magnitude (as well as expected behavior of the overall aftershock sequence). However, such procedures do not provide answers to inquiries about long-range interactions, either retrospectively for interaction with prior remote large events or prospectively for interaction with future remote large events. Dynamic triggering that may be involved in such long-range interactions occurs, often with significant temporal delay, but is not well-understood, making it difficult to respond to related inquiries. One approach to addressing such inquiries is to provide retrospective or prospective occurrence histories for large earthquakes based on global catalogs; while not providing quantitative understanding of any physical interaction, experience-based guidance on the (typically very low) chances of causal interactions can inform public understanding of likelihood of specific scenarios they are commonly very interested in.&lt;/p&gt;

scholarly journals A Hepatitis C Virus cis-Acting Replication Element Forms a Long-Range RNA-RNA Interaction with Upstream RNA Sequences in NS5B

2008 ◽  
Vol 82 (18) ◽  
pp. 9008-9022 ◽  
Author(s):  
Sinéad Diviney ◽  
Andrew Tuplin ◽  
Madeleine Struthers ◽  
Victoria Armstrong ◽  
Richard M. Elliott ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Long Range ◽  
Upstream Region ◽  
Fundamental Aspect ◽  
Genome Replication ◽  
Range Interaction ◽  
Stem Loop ◽  
Long Range Interactions ◽  
Rna Interaction

ABSTRACT The genome of hepatitis C virus (HCV) contains cis-acting replication elements (CREs) comprised of RNA stem-loop structures located in both the 5′ and 3′ noncoding regions (5′ and 3′ NCRs) and in the NS5B coding sequence. Through the application of several algorithmically independent bioinformatic methods to detect phylogenetically conserved, thermodynamically favored RNA secondary structures, we demonstrate a long-range interaction between sequences in the previously described CRE (5BSL3.2, now SL9266) with a previously predicted unpaired sequence located 3′ to SL9033, approximately 200 nucleotides upstream. Extensive reverse genetic analysis both supports this prediction and demonstrates a functional requirement in genome replication. By mutagenesis of the Con-1 replicon, we show that disruption of this alternative pairing inhibited replication, a phenotype that could be restored to wild-type levels through the introduction of compensating mutations in the upstream region. Substitution of the CRE with the analogous region of different genotypes of HCV produced replicons with phenotypes consistent with the hypothesis that both local and long-range interactions are critical for a fundamental aspect of genome replication. This report further extends the known interactions of the SL9266 CRE, which has also been shown to form a “kissing loop” interaction with the 3′ NCR (P. Friebe, J. Boudet, J. P. Simorre, and R. Bartenschlager, J. Virol. 79:380-392, 2005), and suggests that cooperative long-range binding with both 5′ and 3′ sequences stabilizes the CRE at the core of a complex pseudoknot. Alternatively, if the long-range interactions were mutually exclusive, the SL9266 CRE may function as a molecular switch controlling a critical aspect of HCV genome replication.

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