scholarly journals Observation of magnetically tunable Feshbach resonances in ultracold 23Na40K + 40K collisions

Science ◽  
2019 ◽  
Vol 363 (6424) ◽  
pp. 261-264 ◽  
Author(s):  
Huan Yang ◽  
De-Chao Zhang ◽  
Lan Liu ◽  
Ya-Xiong Liu ◽  
Jue Nan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Ground State ◽  
Energy Surface ◽  
Feshbach Resonances ◽  
Field Range ◽  
Ultracold Collisions ◽  
Three Body ◽  
Body Potential ◽  
The Magnetic Field ◽  
Potassium 40

Resonances in ultracold collisions involving heavy molecules are difficult to simulate theoretically and have proven challenging to detect. Here we report the observation of magnetically tunable Feshbach resonances in ultracold collisions between potassium-40 (40K) atoms and sodium-23–potassium-40 (23Na40K) molecules in the rovibrational ground state. We prepare the atoms and molecules in various hyperfine levels of their ground states and observe the loss of molecules as a function of the magnetic field. The atom-molecule Feshbach resonances are identified by observing an enhancement of the loss. We have observed 11 resonances in the magnetic field range of 43 to 120 gauss. The observed atom-molecule Feshbach resonances at ultralow temperatures probe the three-body potential energy surface with exceptional resolution and will help to improve understanding of ultracold collisions.

MAGNETIC FIELD DEPENDENCE OF CRITICAL CURRENTS IN SUPERCONDUCTING POLYCRYSTALS

1992 ◽  
Vol 06 (03) ◽  
pp. 161-169 ◽  
Author(s):  
K.I. KUGEL ◽  
T. YU. LISOVSKAYA ◽  
R.G. MINTS
Keyword(s):  
Magnetic Field ◽  
Magnetic Field Dependence ◽  
Asymptotic Form ◽  
Critical Currents ◽  
Transport Current ◽  
Wide Field ◽  
London Penetration Depth ◽  
Field Range ◽  
Crystallographic Axes ◽  
The Magnetic Field

We study the dependence of critical current j c on magnetic field H in superconducting polycrystals which are considered as systems of superconducting crystallites (isotropic or anisotropic) with Josephson contacts between them. Isotropy or anisotropy of contacts depends on the orientation of their crystallographic axes relatively to edges of contact planes. It is shown that for a system of randomly oriented isotropic contacts, the dependence j c (H) in a relatively wide field range has the asymptotic form j c ~( ln H)/H2. This differs drastically from j c (H) for single contacts. Anisotropy effects due to large differences in London penetration depth λ values corresponding to external magnetic field directed along different axes are analyzed in detail. It is shown that for uniaxal crystals with λ1=λ2≪λ3, this anisotropy leads to the relation [Formula: see text] for chaotic orientation of crystallites. The form of j c (H) curves for two different orientations of the magnetic field relatively to the transport current through the sample is found.

scholarly journals Energy Correlations of α-Particles in the 8Be-Nucleus Ground-State Formation Channel of the 12C(γ,3α) and 16O(γ,4α) Reactions

2019 ◽  
Vol 64 (9) ◽  
pp. 787
Author(s):  
S. N. Afanasyev
Keyword(s):  
Magnetic Field ◽  
Photon Energy ◽  
Relative Motion ◽  
Cross Sections ◽  
Ground State ◽  
Diffusion Chamber ◽  
Mechanism Of Interaction ◽  
The Magnetic Field ◽  
Maximum Photon ◽  
Α Particles

The method of diffusion chamber in the magnetic field making use of a bremsstrahlung beam with a maximum photon energy of 150 MeV is applied to study the 12C(y,3a) and 16O(y,4a) reactions. A resonance identified as the ground state of 8Be nucleus is found in the distribution of events over the energy of the relative motion of two a-particles. The partial cross-sections of the 8Be nucleus formation channels are measured. It is shown that the mechanism of interaction between a y-quantum and a virtual a-particle pair takes place in this case.

scholarly journals THREE-BODY PHOTODISINTEGRATION OF 4He NUCLEUS BY LINEARLY POLARIZED PHOTONS

2019 ◽  
pp. 11-15
Author(s):  
A.A. Peretiatko ◽  
R.T. Murtazin ◽  
A.F. Khodyachikh
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Production Cross ◽  
Reaction Products ◽  
Azimuthal Distribution ◽  
Proton Production ◽  
Linearly Polarized ◽  
Three Body ◽  
Polarized Photons ◽  
The Magnetic Field

Experimental data are reported from studies of the reaction 4He(γ, pn)d through the use of the streamer chamber placed in the magnetic field and exposed to a linearly polarized photon beam from the electron linac LUE-2000. A structure has been revealed in the momentum distribution of deuterons. Studies were made into the effects of nucleon-deuteron correlation. The azimuthal distribution of reaction products and the asymmetry of proton production cross-section were measured. The obtained data were analyzed in the framework of the quasideuteron model.

GROUND STATE OF N HARMONICALLY BOUND ANYONS IN A MAGNETIC FIELD

1992 ◽  
Vol 07 (38) ◽  
pp. 3593-3600
Author(s):  
R. CHITRA
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Harmonic Oscillator ◽  
Ground State ◽  
Harmonic Frequency ◽  
Oscillator Potential ◽  
Harmonic Oscillator Potential ◽  
Thomas Fermi ◽  
Large N ◽  
The Magnetic Field

The properties of the ground state of N anyons in an external magnetic field and a harmonic oscillator potential are computed in the large-N limit using the Thomas-Fermi approximation. The number of level crossings in the ground state as a function of the harmonic frequency, the strength and the direction of the magnetic field and N are also studied.

SPECTRAL PROPERTIES AND SYMMETRIES OF DOUBLE COVERINGS OF GRAPHS WITH APPLICATIONS TO SUPERCONDUCTIVITY

2005 ◽  
Vol 15 (02) ◽  
pp. 301-324
Author(s):  
JACOB RUBINSTEIN ◽  
MICHELLE SCHATZMAN
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Phase Transitions ◽  
Ground State ◽  
Spectral Properties ◽  
Embedded Graph ◽  
Symmetry Constraints ◽  
The Laplace Operator ◽  
The Magnetic Field ◽  
Double Coverings

Let M be a planar embedded graph, and let [Formula: see text] be its double covering. We count the multiplicity of the ground states of the Laplace operator on [Formula: see text] under certain symmetry constraints. The examples of interest for us are ladder-like graphs made out of n, identical rectangles. We find that in the case of an odd n, the multiplicity of the ground state is 2, and if n, is even, the ground state is simple. This result gives an answer to a conjecture by Parks on the type of phase transitions that can occur in a superconducting ladder: Parks conjectured that in the case when the magnetic field is one half fluxoid per rectangle, the phase transition would be continuous in the case of a ladder made out of two rectangles. Our result indeed implies Parks conjecture and generalizes it to any even ladder. The mathematics of this paper is a mixture of topology, symmetry arguments and comparison theorem between the eigenvalues of Laplace operators on graphs with well chosen boundary conditions.

INFLUENCE OF LATTICE VIBRATION ON THE GROUND STATE OF MAGNETOPOLARON IN A PARABOLIC QUANTUM DOT

2010 ◽  
Vol 24 (27) ◽  
pp. 2705-2712 ◽  
Author(s):  
EERDUNCHAOLU ◽  
WEI XIN ◽  
YUWEI ZHAO
Keyword(s):  
Magnetic Field ◽  
Strong Coupling ◽  
Ground State Energy ◽  
Vibration Frequency ◽  
Ground State ◽  
Weak Coupling ◽  
State Energy ◽  
Cyclotron Frequency ◽  
Lattice Vibration ◽  
The Magnetic Field

Influence of the lattice vibration on the properties of the magnetopolaron in the parabolic quantum dots (QDs) is studied by using the Huybrechts' linear combination operator and Lee–Low–Pines (LLP) transformation methods. The expressions for the vibration frequency and the ground-state energy of the magnetopolaron as functions of the confinement strength of the QDs, the magnetic field and temperature are derived under the strong and weak coupling, respectively. The results of the numerical calculations show that the changes of the vibration frequency and ground-state energy of the magnetopolaron with the confinement strength of the QDs, the magnetic field and temperature are different under different couplings. The vibration frequency and the ground-state energy of the weak-coupling magnetopolaron and the vibration frequency of the strong-coupling magnetopolaron will increase with increase of the confinement strength of the QDs and cyclotron frequency, the vibration frequency and ground-state energy of the strong-coupling magnetopolaron. However, the ground-state energy of the weak-coupling magnetopolaron will decrease with increase of the temperature. The dependence of the ground-state energy of the strong-coupling magnetopolaron on the confinement strength of the QDs and cyclotron frequency is strongly influenced by the temperature. The remarkable influence of the temperature on the ground-state energy of the magnetopolaron arises when the temperature is relatively higher.

Article

1998 ◽  
Vol 76 (7) ◽  
pp. 507-513
Author(s):  
O Bolina ◽  
J R Parreira
Keyword(s):  
Magnetic Field ◽  
Transverse Magnetic Field ◽  
Ground State ◽  
Linear Chain ◽  
Critical Value ◽  
Transverse Magnetic ◽  
The State ◽  
Xy Model ◽  
The Magnetic Field

We show that the ground state of the xy model (ferromagnetic orantiferromagnetic) in a transverse magnetic field h --- for any spin value, in any dimension --- is the state with all spins aligned antiparallel to the field when h is greater than some critical value hc. In particular, for the spin-1/2 linear chain, we study the behavior of correlations as functions of the magnetic field. PACS Nos.: 75.10Jm and 64.60.Cm

scholarly journals Магнитосопротивление и квантовые осцилляции в полуметалле WTe-=SUB=-2-=/SUB=-

2021 ◽  
Vol 63 (12) ◽  
pp. 2033
Author(s):  
А.Л. Пирозерский ◽  
Е.В. Чарная ◽  
M.K. Lee ◽  
L.-J. Chang ◽  
С.В. Наумов ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Field Range ◽  
Magnetic Field Range ◽  
Fundamental Frequencies ◽  
Shubnikov De Haas Oscillations ◽  
The Magnetic Field ◽  
Strong Spin

The discovery of extreme magnetoresistance (XMR) in non-magnetic materials attracted attention to the WTe2 semimetal. We have carried out studies of magnetoresistance in a tungsten ditelluride single crystal in the magnetic field range up to 14 T. Magnetoresistance increased with increasing field following a near quadratic law without saturation. The Shubnikov-de Haas oscillations were observed. Four fundamental frequencies were found in the oscillations spectrum, which correspond to two electron and two hole pockets caused by strong spin-orbit coupling.

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