Sobolev maps with integer degree and applications to Skyrme’s problem

1992 ◽  
Vol 436 (1896) ◽  
pp. 197-201 ◽  
Keyword(s):  
Finite Energy ◽  
Natural Class ◽  
Sobolev Maps

Let ɸ : R 3 → S 3 ⊂ R 4 , ∣ A ( ɸ )∣ 2 ═ Ʃ 3 α,β═1 │∂ ɸ /∂ x α ∧ ∂ ɸ /∂ x β ∣ 2 and let k ϵ Z . Skyrme's problem consists in minimizing the energy ε( ɸ ) : ═ ∫ R 3 ∣∇ ɸ ∣ 2 + ∣ A ( ɸ )∣ 2 d x among maps with degree k ═ d ( ɸ ) : ═ 1/2π 2 ∫ R 3 det ( ɸ , ∇ ɸ ) d x . We show that for all ɸ with finite energy d ( ɸ ) is an integer and then obtain existence of a minimizer of ε in the natural class of maps with finite energy.

scholarly journals THE PONTRJAGIN–HOPF INVARIANTS FOR SOBOLEV MAPS

2010 ◽  
Vol 12 (01) ◽  
pp. 121-181 ◽  
Author(s):  
DAVE AUCKLY ◽  
LEV KAPITANSKI
Keyword(s):  
Sobolev Spaces ◽  
Finite Energy ◽  
Homotopy Classification ◽  
Smooth Maps ◽  
Sobolev Maps ◽  
Complete Set ◽  
Integral Degree ◽  
Energy Maps ◽  
Faddeev Model ◽  
Homotopy Invariants

Subtle issues arise when extending homotopy invariants to spaces of functions having little regularity, e.g., Sobolev spaces containing discontinuous functions. Sometimes it is not possible to extend the invariant at all, and sometimes, even when the formulas defining the invariants make sense, they may not have expected properties (e.g., there are maps having non-integral degree).In this paper, we define a complete set of homotopy invariants for maps from three-manifolds to the two-sphere and show that these invariants extend to finite Faddeev energy maps and maps in suitable Sobolev spaces. For smooth maps, our description is proved to be equivalent to Pontrjagin's original homotopy classification from the 1930's. We further show that for the finite energy maps the invariants take on exactly the same values as for smooth maps. We include applications to the Faddeev model.The techniques that we use would also apply to many more problems and/or other functionals. We have tried to make the paper accessible to analysts, geometers and mathematical physicists.

scholarly journals GAUGE THEORY OF FADDEEV–SKYRME FUNCTIONALS

2010 ◽  
Vol 12 (05) ◽  
pp. 871-908
Author(s):  
SERGIY KOSHKIN
Keyword(s):  
Homotopy Class ◽  
Homogeneous Spaces ◽  
Variational Problems ◽  
Finite Energy ◽  
Energy Functional ◽  
Target Space ◽  
Homotopy Classes ◽  
Existence Of Minimizers ◽  
Sobolev Maps ◽  
Geometric Variational Problems

We study geometric variational problems for a class of nonlinear σ-models in quantum field theory. Mathematically, one needs to minimize an energy functional on homotopy classes of maps from closed 3-manifolds into compact homogeneous spaces G/H. The minimizers are known as Hopfions and exhibit localized knot-like structure. Our main results include proving existence of Hopfions as finite energy Sobolev maps in each (generalized) homotopy class when the target space is a symmetric space. For more general spaces, we obtain a weaker result on existence of minimizers in each 2-homotopy class.Our approach is based on representing maps into G/H by equivalence classes of flat connections. The equivalence is given by gauge symmetry on pullbacks of G → G/H bundles. We work out a gauge calculus for connections under this symmetry, and use it to eliminate non-compactness from the minimization problem by fixing the gauge.

scholarly journals Stabilization of Finite-Energy Gottesman-Kitaev-Preskill States

2020 ◽  
Vol 125 (26) ◽  
Author(s):  
Baptiste Royer ◽  
Shraddha Singh ◽  
S. M. Girvin
Keyword(s):  
Finite Energy

scholarly journals Asymptotic symmetries and celestial CFT

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Laura Donnay ◽  
Sabrina Pasterski ◽  
Andrea Puhm
Keyword(s):  
Principal Series ◽  
Finite Energy ◽  
Continuous Series ◽  
Asymptotic Symmetry ◽  
Null Infinity ◽  
Conformal Dimension ◽  
Contour Integrals ◽  
Celestial Sphere ◽  
Goldstone Modes ◽  
Asymptotic Symmetries

Abstract We provide a unified treatment of conformally soft Goldstone modes which arise when spin-one or spin-two conformal primary wavefunctions become pure gauge for certain integer values of the conformal dimension ∆. This effort lands us at the crossroads of two ongoing debates about what the appropriate conformal basis for celestial CFT is and what the asymptotic symmetry group of Einstein gravity at null infinity should be. Finite energy wavefunctions are captured by the principal continuous series ∆ ∈ 1 + iℝ and form a complete basis. We show that conformal primaries with analytically continued conformal dimension can be understood as certain contour integrals on the principal series. This clarifies how conformally soft Goldstone modes fit in but do not augment this basis. Conformally soft gravitons of dimension two and zero which are related by a shadow transform are shown to generate superrotations and non-meromorphic diffeomorphisms of the celestial sphere which we refer to as shadow superrotations. This dovetails the Virasoro and Diff(S2) asymptotic symmetry proposals and puts on equal footing the discussion of their associated soft charges, which correspond to the stress tensor and its shadow in the two-dimensional celestial CFT.

scholarly journals Dynamic Quantum Games

2021 ◽  
Author(s):  
Vassili N. Kolokoltsov
Keyword(s):  
Real Time ◽  
Repeated Games ◽  
Dynamic Games ◽  
Quantum Control ◽  
Diffusion Processes ◽  
Natural Class ◽  
Quantum Games ◽  
Technical Problems ◽  
Modern Development ◽  
Starting Point

AbstractQuantum games represent the really twenty-first century branch of game theory, tightly linked to the modern development of quantum computing and quantum technologies. The main accent in these developments so far was made on stationary or repeated games. In this paper, we aim at initiating the truly dynamic theory with strategies chosen by players in real time. Since direct continuous observations are known to destroy quantum evolutions (so-called quantum Zeno paradox), the necessary new ingredient for quantum dynamic games must be the theory of non-direct observations and the corresponding quantum filtering. Apart from the technical problems in organizing feedback quantum control in real time, the difficulty in applying this theory for obtaining mathematically amenable control systems is due partially to the fact that it leads usually to rather non-trivial jump-type Markov processes and/or degenerate diffusions on manifolds, for which the corresponding control is very difficult to handle. The starting point for the present research is the remarkable discovery (quite unexpected, at least to the author) that there exists a very natural class of homodyne detections such that the diffusion processes on projective spaces resulting by filtering under such arrangements coincide exactly with the standard Brownian motions (BM) on these spaces. In some cases, one can even reduce the process to the plain BM on Euclidean spaces or tori. The theory of such motions is well studied making it possible to develop a tractable theory of related control and games, which can be at the same time practically implemented on quantum optical devices.

scholarly journals Null controllability of a thermoelastic plate

2002 ◽  
Vol 7 (11) ◽  
pp. 585-599 ◽  
Author(s):  
Assia Benabdallah ◽  
Maria Grazia Naso
Keyword(s):  
Thermal Control ◽  
Finite Energy ◽  
Null Controllability ◽  
Energy Solution ◽  
Plate Model ◽  
Time And Space ◽  
Thermal Equation ◽  
Control Time ◽  
Thermoelastic Plate ◽  
Finite Energy Solution

Thermoelastic plate model with a control term in the thermal equation is considered. The main result in this paper is that with thermal control, locally distributed within the interior and square integrable in time and space, any finite energy solution can be driven to zero at the control timeT.

Finite-energy sum rules and the reactions ee → eeϵ (750) and ee → eef (1260)

1971 ◽  
Vol 36 (5) ◽  
pp. 463-466 ◽  
Author(s):  
B. Schrempp-Otto ◽  
F. Schrempp ◽  
T.F. Walsh
Keyword(s):  
Sum Rules ◽  
Finite Energy

FINITE ENERGY ONE-HALF MONOPOLE SOLUTIONS

2012 ◽  
Vol 27 (40) ◽  
pp. 1250233 ◽  
Author(s):  
ROSY TEH ◽  
BAN-LOONG NG ◽  
KHAI-MING WONG
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Topological Charge ◽  
Magnetic Monopole ◽  
Magnetic Charge ◽  
Finite Energy ◽  
Spatial Infinity ◽  
Yang Mills ◽  
The Magnetic Field

We present finite energy SU(2) Yang–Mills–Higgs particles of one-half topological charge. The magnetic fields of these solutions at spatial infinity correspond to the magnetic field of a positive one-half magnetic monopole at the origin and a semi-infinite Dirac string on one-half of the z-axis carrying a magnetic flux of [Formula: see text] going into the origin. Hence the net magnetic charge is zero. The gauge potentials are singular along one-half of the z-axis, elsewhere they are regular.

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