scholarly journals U(1)symmetry breaking and violated axial symmetry inTlCuCl3and other insulating spin systems

2009 ◽  
Vol 79 (1) ◽  
Author(s):  
Raffaele Dell’Amore ◽  
Andreas Schilling ◽  
Karl Krämer
Keyword(s):  
Symmetry Breaking ◽  
Axial Symmetry ◽  
Spin Systems

S=1 antiferromagnetic Heisenberg chain with an axial-symmetry-breaking anisotropy

1991 ◽  
Vol 44 (18) ◽  
pp. 10385-10388 ◽  
Author(s):  
Tiôru Sakai ◽  
Minoru Takahashi
Keyword(s):  
Symmetry Breaking ◽  
Axial Symmetry ◽  
Heisenberg Chain

scholarly journals Molecular mechanism of symmetry breaking in a 3D model of a human epiblast

2018 ◽  
Author(s):  
Mijo Simunovic ◽  
Jakob J. Metzger ◽  
Fred Etoc ◽  
Anna Yoney ◽  
Albert Ruzo ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Axial Symmetry ◽  
3D Model ◽  
Epithelial To Mesenchymal Transition ◽  
Embryonic Stem ◽  
Primitive Streak ◽  
Molecular Evidence ◽  
Axis Formation ◽  
Mesenchymal Transition

ABSTRACTBreaking the anterior-posterior (AP) symmetry in mammals takes place at gastrulation. Much of the signaling network underlying this process has been elucidated in the mouse, however there is no direct molecular evidence of events driving axis formation in humans. Here, we use human embryonic stem cells to generate an in vitro 3D model of a human epiblast whose size, cell polarity, and gene expression are similar to a 10-day human epiblast. A defined dose of bone mor-phogenetic protein 4 (BMP4) spontaneously breaks axial symmetry, and induces markers of the primitive streak and epithelial to mesenchymal transition. By gene knockouts and live-cell imaging we show that, downstream of BMP4, WNT3 and its inhibitor DKK1 play key roles in this process. Our work demonstrates that a model human epiblast can break axial symmetry despite no asymmetry in the initial signal and in the absence of extraembryonic tissues or maternal cues. Our 3D model opens routes to capturing molecular events underlying axial symmetry breaking phenomena, which have largely been unexplored in model human systems.

scholarly journals Probing Axial Symmetry Breaking in the Galaxy with Gaia Data Release 2

2020 ◽  
Vol 893 (2) ◽  
pp. 105
Author(s):  
Austin Hinkel ◽  
Susan Gardner ◽  
Brian Yanny
Keyword(s):  
Symmetry Breaking ◽  
Axial Symmetry ◽  
Data Release ◽  
The Galaxy

Spin nematics revisited

2002 ◽  
Vol 12 (9) ◽  
pp. 265-265
Author(s):  
V. Cvetkovic ◽  
J. Zaanen ◽  
Z. Nussinov
Keyword(s):  
Form Factor ◽  
Symmetry Breaking ◽  
Gauge Invariance ◽  
Degrees Of Freedom ◽  
Higher Dimensions ◽  
Energy Scale ◽  
Spin Systems ◽  
Heisenberg Spin ◽  
Nematic Order ◽  
Dynamical Algebra

Biquadratic spin 1 Heisenberg spin systems can be constructed exhibiting spin nematic order in higher dimensions. In terms of the original spin degrees of freedom, the spontaneous nematic symmetry breaking generates a Z2 gauge invariance. Using a generalized Holstein-Primakoff transformation for the underlying U(3) dynamical algebra, we calculate the spin dynamical form factor. Although spin is not a gauge singlet, we find form factor to be finite at finite q and $$\backslash$omega$\backslash$$, contrary to our expectations regarding the presence of a energy scale protecting the gauge invariance. This result appears to be perturbatively stable.

scholarly journals Spin Hamilton Operators, Symmetry Breaking, Energy Level Crossing, and Entanglement

2012 ◽  
Vol 67 (10-11) ◽  
pp. 608-612
Author(s):  
Willi-Hans Steeb ◽  
Yorick Hardy ◽  
Jacqueline de Greef
Keyword(s):  
Energy Spectrum ◽  
Energy Level ◽  
Symmetry Breaking ◽  
Hilbert Spaces ◽  
Spin Systems ◽  
Level Crossing ◽  
Finite Dimensional ◽  
Breaking Energy ◽  
Coupled Spin Systems

We study finite-dimensional product Hilbert spaces, coupled spin systems, entanglement, and energy level crossing. The Hamilton operators are based on the Pauli group.We show that swapping the interacting term can lead from unentangled eigenstates to entangled eigenstates and from an energy spectrum with energy level crossing to avoided energy level crossing.

scholarly journals Axial symmetry breaking of Saturn’s thermosphere

2012 ◽  
Vol 422 (2) ◽  
pp. 1460-1488 ◽  
Author(s):  
C. G. A. Smith ◽  
N. Achilleos
Keyword(s):  
Symmetry Breaking ◽  
Axial Symmetry

Axial-symmetry breaking in constrained membranes

2009 ◽  
Vol 367 (1902) ◽  
pp. 3363-3378 ◽  
Author(s):  
Paolo Biscari ◽  
Gaetano Napoli
Keyword(s):  
Symmetry Breaking ◽  
Axial Symmetry ◽  
Lipid Membrane ◽  
Equilibrium Configuration ◽  
Critical Threshold ◽  
Fourier Mode ◽  
Planar Approximation ◽  
Axisymmetric Mode ◽  
Equilibrium Shapes ◽  
Energy Minimizers

We study the equilibrium shapes of a lipid membrane, attached to a fixed circular substrate. We show how the weakening of the boundary conditions is able to break the axial symmetry of the optimal equilibrium configuration. We derive the critical threshold of the symmetry-breaking transition, and obtain the analytical expression of the free-energy minimizers in the quasi-planar approximation. Metastable states turn out to contain contributions only from the axisymmetric mode, and at most one single non-trivial Fourier mode.

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