Results 51 to 60 of about 38,188 (251)

Advanced control of non‐isothermal axial dispersion tubular reactors with recycle‐induced state delay

The Canadian Journal of Chemical Engineering, EarlyView.
Abstract We develop a delay‐aware estimation and control framework for a non‐isothermal axial dispersion tubular reactor modelled as a coupled parabolic‐hyperbolic PDE system with recycle‐induced state delay. The infinite‐dimensional dynamics are preserved without spatial discretization by representing the delay as a transport PDE and adopting a late ...
Behrad Moadeli, Stevan Dubljevic
wiley   +1 more source

The Hahn-Exton q-Bessel function as the characteristic function of a Jacobi matrix

Special Matrices, 2014
A family T(ν), ν ∈ ℝ, of semiinfinite positive Jacobi matrices is introduced with matrix entries takenfrom the Hahn-Exton q-difference equation. The corresponding matrix operators defined on the linear hullof the canonical basis in ℓ2(ℤ+) are essentially
Štampach F., Šťovíček P.
doaj   +1 more source

Near-horizon modes and self-adjoint extensions of the Schroedinger operator

, 2018
We investigate the dynamics of scalar fields in the near-horizon exterior region of a Schwarzschild black hole. We show that low-energy modes are typically long-living and might be considered as being confined near the black hole horizon.
Balachandran, A. P., de Queiroz, A. R., Saa, Alberto   +2 more
core   +1 more source

The Huang–Yang Formula for the Low‐Density Fermi Gas: Upper Bound

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We study the ground state energy of a gas of spin 1/2$1/2$ fermions with repulsive short‐range interactions. We derive an upper bound that agrees, at low density ϱ$\varrho$, with the Huang–Yang conjecture. The latter captures the first three terms in an asymptotic low‐density expansion, and in particular the Huang–Yang correction term of order
Emanuela L. Giacomelli, Christian Hainzl, Phan Thành Nam, Robert Seiringer   +3 more
wiley   +1 more source

Invariant Measure and Universality of the 2D Yang–Mills Langevin Dynamic

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We prove that the Yang–Mills (YM) measure for the trivial principal bundle over the two‐dimensional torus, with any connected, compact structure group, is invariant for the associated renormalised Langevin dynamic. Our argument relies on a combination of regularity structures, lattice gauge‐fixing and Bourgain's method for invariant measures ...
Ilya Chevyrev, Hao Shen
wiley   +1 more source

Unitary evolution and cosmic acceleration in Loop Quantum Cosmology

Physics Letters B
Loop quantum cosmology was shown to interpolate between de Sitter and FLRW Universe phases through a bounce by including Euclidean and Lorentzian terms of the Hamiltonian constraint with weight one -that corresponding to classical General Relativity ...
Omar Gallegos, Tonatiuh Matos, Hugo A. Morales-Técotl   +2 more
doaj   +1 more source

Stability Bounds for the Generalized Kadanoff‐Baym Ansatz in the Holstein Dimer

Contributions to Plasma Physics, EarlyView.
ABSTRACT Predicting real‐time dynamics in correlated systems is demanding: exact two‐time Green's function methods are accurate but often too costly, while the Generalized Kadanoff‐Baym Ansatz (GKBA) offers time‐linear propagation at the risk of uncontrolled behavior. We examine when and why GKBA fails in a minimal yet informative setting, the Holstein
Oscar Moreno Segura, Yaroslav Pavlyukh, Riku Tuovinen   +2 more
wiley   +1 more source

Quantum Spin Dynamics (QSD) II [PDF]

, 1996
We continue here the analysis of the previous paper of the Wheeler-DeWitt constraint operator for four-dimensional, Lorentzian, non-perturbative, canonical vacuum quantum gravity in the continuum. In this paper we derive the complete kernel, as well as a
, , Ashtekar A, Ashtekar A, Ashtekar A, Baez J, Baez J, Baez J, Brügmann B, Higuchi A, Higuchi A, Marolf D, Marolf D, Reed M, T Thiemann, Thiemann T, Thiemann T, Thiemann T, Thiemann T, Thiemann T, Thiemann T Complete formula for the matrix elements of the volume operator in canonical quantum gravity, Thiemann T The length operator in canonical quantum gravity   +21 more
core   +6 more sources

Efficient First‐Principles Inverse Design of Nanolasers

Laser &Photonics Reviews, EarlyView.
This article introduces a first‐principles inverse‐design framework for nanolasers that directly incorporates nonlinear lasing physics. By unifying steady‐state ab‐initio laser theory (SALT) with topology optimization, it reveals how spatial hole burning, gain saturation, and cavity‐emitter coupling shape laser performance, enabling efficient discovery
Beñat Martinez de Aguirre Jokisch, Alexander Cerjan, Rasmus Ellebæk Christiansen, Jesper Mørk, Ole Sigmund, Steven G. Johnson   +5 more
wiley   +1 more source

Nonself-Adjoint Second-Order Difference Operators in Limit-Circle Cases

Abstract and Applied Analysis, 2012
We consider the maximal dissipative second-order difference (or discrete Sturm-Liouville) operators acting in the Hilbert space ℓ2𝑤(ℤ) (ℤ:={0,±1,±2,…}), that is, the extensions of a minimal symmetric operator with defect index (2,2) (in the Weyl ...
Bilender P. Allahverdiev
doaj   +1 more source