scholarly journals Cooling through quantum criticality and many-body effects in condensed matter and cold gases

2014 ◽  
Vol 28 (26) ◽  
pp. 1430017 ◽  
Author(s):  
Bernd Wolf ◽  
Andreas Honecker ◽  
Walter Hofstetter ◽  
Ulrich Tutsch ◽  
Michael Lang
Keyword(s):  
Condensed Matter ◽  
Main Idea ◽  
Point Of View ◽  
Ultracold Gases ◽  
Theoretical Point ◽  
Many Body ◽  
Cold Gases ◽  
Recent Developments ◽  
Body Cooling ◽  
Many Body Interactions

This article reviews some recent developments for new cooling technologies in the fields of condensed matter physics and cold gases, both from an experimental and theoretical point of view. The main idea is to make use of distinct many-body interactions of the system to be cooled which can be some cooling stage or the material of interest itself, as is the case in ultracold gases. For condensed matter systems, we discuss magnetic cooling schemes based on a large magnetocaloric effect as a result of a nearby quantum phase transition and consider effects of geometrical frustration. For ultracold gases, we review many-body cooling techniques, such as spin-gradient and Pomeranchuk cooling, which can be applied in the presence of an optical lattice. We compare the cooling performance of these new techniques with that of conventional approaches and discuss state-of-the-art applications.

Low-energy Ion Beam Biotechnology at Chiang Mai University

2009 ◽  
Vol 1181 ◽  
Author(s):  
Liangdeng Yu ◽  
S. Anuntalabhochai
Keyword(s):  
Gene Transfer ◽  
Biological Effects ◽  
Ion Beam ◽  
Point Of View ◽  
Low Energy ◽  
Theoretical Point ◽  
Chiang Mai ◽  
Naked Dna ◽  
Recent Developments ◽  
Cell Envelopes

AbstractMeV-ion beam has long been applied to biology research and applications for many decades as highly energetic ions are undoubtedly able to interact directly with biology molecules to cause changes in biology. However, low-energy ion beam at tens of keV and even lower has also been found to have significant biological effects on living materials. The finding has led to applications of ion-beam induced mutation and gene transfer. From the theoretical point of view, the low-energy ion beam effects on biology are difficult to understand since the ion range is so short that the ions can hardly directly interact with the key biological molecules for the changes. This talk introduces interesting aspects of low-energy ion beam biology, including basis of ion beam biotechnology and recent developments achieved in Chiang Mai University in relevant applications such as mutation and gene transfer and investigations on mechanisms involved in the low-energy ion interaction with biological matter such as eV-keV ion beam bombardments of naked DNA and the cell envelopes.

Radial basis functions

Acta Numerica ◽  
2000 ◽  
Vol 9 ◽  
pp. 1-38 ◽  
Author(s):  
M. D. Buhmann
Keyword(s):  
Radial Basis Function ◽  
Radial Basis Functions ◽  
Basis Function ◽  
Convergence Rates ◽  
Basis Functions ◽  
Point Of View ◽  
Theoretical Point ◽  
Grid Data ◽  
Radial Basis ◽  
Recent Developments

Radial basis function methods are modern ways to approximate multivariate functions, especially in the absence of grid data. They have been known, tested and analysed for several years now and many positive properties have been identified. This paper gives a selective but up-to-date survey of several recent developments that explains their usefulness from the theoretical point of view and contributes useful new classes of radial basis function. We consider particularly the new results on convergence rates of interpolation with radial basis functions, as well as some of the various achievements on approximation on spheres, and the efficient numerical computation of interpolants for very large sets of data. Several examples of useful applications are stated at the end of the paper.

scholarly journals Thomas-Fermi Model in the Presence of Natural Cutoffs

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Kourosh Nozari ◽  
Z. Haghani ◽  
J. Vahedi
Keyword(s):  
Quantum Gravity ◽  
Condensed Matter ◽  
Condensed Matter Physics ◽  
Many Body ◽  
Fermi Model ◽  
Thomas Fermi ◽  
Doubly Special Relativity ◽  
Gravity Effects ◽  
Arbitrary Precision ◽  
Many Body Interactions

It has been revealed, in the context of quantum gravity candidates, that measurement of position cannot be done with arbitrary precision and there is a finite resolution of space-time points. This leads naturally to a minimal measurable length of the order of Planck length. Also, in the context of newly proposed doubly special relativity theories, a test particle’s momentum cannot be arbitrarily imprecise leading nontrivially to a maximal momentum for a test particle. These two natural cutoffs affects most of quantum field theoretic arguments in the spirit of condensed matter physics. Here we focus on the role of these natural cutoffs on Thomas-Fermi theory in condensed matter physics. We show how quantum gravity effects can play important role phenomenologically in many-body interactions of solids.

scholarly journals THEORETICAL QUANTUM-INFORMATION PROPERTIES OF NUCLEI AND TRAPPED BOSE GASES

2005 ◽  
Vol 14 (07) ◽  
pp. 1087-1104 ◽  
Author(s):  
CH. C. MOUSTAKIDIS ◽  
K. CH. CHATZISAVVAS ◽  
C. P. PANOS
Keyword(s):  
Short Range ◽  
Point Of View ◽  
Theoretical Point ◽  
Many Body ◽  
Information Measures ◽  
Atomic Nuclei ◽  
Many Body Systems ◽  
Bose Einstein ◽  
Jensen Shannon Divergence ◽  
Short Range Correlations

We will study fermionic systems like atomic nuclei and bosonic systems like the correlated atoms in a trap from an information-theoretical point of view. The Shannon and Onicescu information measures are calculated for the above systems by comparing the correlated and uncorrelated cases as functions of the strength of the short range correlations. One-body and two-body density and momentum distributions are employed. Thus, the effect of short-range correlations on the information content is evaluated. The magnitude of distinguishability between the correlated and uncorrelated densities is also discussed employing suitable measures for the distance of states i.e. the well known Kullback–Leibler relative entropy and the recently proposed Jensen–Shannon divergence entropy. We will see that the same information-theoretical properties hold for quantum many-body systems obeying Bose–Einstein and Fermi–Dirac (statistics).

QUANTUM KINETIC THEORY FOR A BOSE-EINSTEIN CONDENSED ALKALI GAS

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1641-1650
Author(s):  
M. J. HOLLAND ◽  
J. COOPER ◽  
R. WALSER
Keyword(s):  
Quantum Correlations ◽  
Point Of View ◽  
Einstein Condensation ◽  
Theoretical Point ◽  
Equilibrium System ◽  
Many Body ◽  
Effective Interactions ◽  
Dilute Gas ◽  
The Many ◽  
Bose Einstein

The most salient features of the Bose-Einstein condensation of a magnetically confined alkali vapor is the diluteness of the gas and the extremely weak effective interactions. From a theoretical point of view, the interesting aspect is the potential formulation of the many-body quantum theory for a non-uniform and potentially non-equilibrium system founded entirely on microscopic physics. The crucial postulate is the rapid attenuation of many particle quantum correlations in the dilute system which can be motivated from universal considerations. In principle, it will be possible to provide direct comparison between theory and experiment over all temperature scales with no phenomenological parameters — a challenge facing the theoretical community in the near future. The dilute gas experiments provide an exciting stage on which to build bridges linking the theory of complex and collective phenomena in superconducting and superfluid systems, with the single particle microscopic physics described in quantum optics and laser physics.

scholarly journals Ultrafast Multidimensional Spectroscopy with Field Resolution and Noncollinear Geometry at Mid-Infrared Frequencies

2022 ◽  
Author(s):  
Thomas Deckert ◽  
Jonas Allerbeck ◽  
Takayuki Kurihara ◽  
Daniele Brida
Keyword(s):  
Indium Antimonide ◽  
Condensed Matter ◽  
Low Energy ◽  
Modulation Scheme ◽  
Many Body ◽  
Advanced Technique ◽  
Mid Infrared ◽  
Multidimensional Spectroscopy ◽  
Infrared Frequencies ◽  
Many Body Interactions

Abstract Energetic correlations and their dynamics govern the fundamental properties of condensed matter materials. Ultrafast multidimensional spectroscopy in the mid infrared is an advanced technique to study such coherent low-energy dynamics. The intrinsic many-body phenomena in functional solid-state materials, in particular few-layer samples, remain widely unexplored to this date, because complex and weak sample responses demand versatile and sensitive detection. Here, we present a novel setup for ultrafast multidimensional spectroscopy with noncollinear geometry and complete field resolution in the 15-40 THz range. Electric fields up to few-100 kV cm-1 drive coherent dynamics in a perturbative regime, and an advanced modulation scheme allows to detect nonlinear signals down to a few tens of V cm-1 entirely background-free with high sensitivity and full control over the geometric phase-matching conditions. Our system aims at the investigation of correlations and many-body interactions in condensed matter systems at low energy. Benchmark measurements on bulk indium antimonide (InSb) reveal a strong six-wave mixing signal and map ultrafast changes of the band structure with access to amplitude and phase information. Our results pave the way towards the investigation of functional thin film materials and few-layer samples.

Timber Auctions in the Context of the Modern Auction Theory

2007 ◽  
pp. 86-94
Author(s):  
A. Manakov
Keyword(s):  
Theoretical Analysis ◽  
Auction Theory ◽  
Point Of View ◽  
Theoretical Point ◽  
English Auction ◽  
Analysis And Evaluation

The article provides theoretical analysis and evaluation of the timber auctions reforms in Russia. The author shows that the mechanism of the "combined auctions", which functioned until recently, is more appropriate from the theoretical point of view (and from the point of view of the Russian practice) as compared to the officially approved format of the English auction.

A novel cryptosystem based on abstract automata and Latin cubes

2015 ◽  
Vol 52 (2) ◽  
pp. 221-232
Author(s):  
Pál Dömösi ◽  
Géza Horváth
Keyword(s):  
Block Cipher ◽  
Finite Automata ◽  
Theoretical Background ◽  
Point Of View ◽  
Theoretical Point ◽  
Transition Matrices ◽  
Encryption And Decryption ◽  
Secret Keys ◽  
Automata Network ◽  
Fully Functioning

In this paper we introduce a novel block cipher based on the composition of abstract finite automata and Latin cubes. For information encryption and decryption the apparatus uses the same secret keys, which consist of key-automata based on composition of abstract finite automata such that the transition matrices of the component automata form Latin cubes. The aim of the paper is to show the essence of our algorithms not only for specialists working in compositions of abstract automata but also for all researchers interested in cryptosystems. Therefore, automata theoretical background of our results is not emphasized. The introduced cryptosystem is important also from a theoretical point of view, because it is the first fully functioning block cipher based on automata network.

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