Morris-Shore transformation for nondegenerate systems

Extension of the Morris-Shore transformation to multilevel ladders

We describe situations in which chains of N degenerate quantum energy levels, coupled by time-dependent external fields, can be replaced by independent sets of chains of length N, N−1, . . . ,2 and sets of uncoupled single states. The transformation is a generalization of the two-level Morris-Shore transformation J.R. Morris and B.W. Shore, Phys. Rev. A 27, 906 1983 . We illustrate the procedur...

channel estimation for mimo-ofdm systems

تخمین دقیق مشخصات کانال در سیستم های مخابراتی یک امر مهم محسوب می گردد. این امر به ویژه در کانال های بیسیم با ‏خاصیت فرکانس گزینی و زمان گزینی شدید، چالش بزرگی است. مقالات متعدد پر از روش های مبتکرانه ای برای طراحی و آنالیز ‏الگوریتم های تخمین کانال است که بیشتر آنها از روش های خاصی استفاده می کنند که یا دارای عملکرد خوب با پیچیدگی ‏محاسباتی بالا هستند و یا با عملکرد نه چندان خوب پیچیدگی پایینی...

Nondegenerate Representations of Continuous Product Systems

We show that every (continuous) faithful product system admits a (continuous) faithful nondegenerate representation. For Hilbert spaces this is equivalent to Arveson’s result that every Arveson system comes from an E0–semigroup. We point out that for Hilbert modules this is not so. As applications we show a C–algebra version of a result for von Neumann algebras due to Arveson and Kishimoto, and...

Analytic Reducibility of Nondegenerate Centers: Cherkas Systems

In this paper we study the center problem for polynomial differential systems and we prove that any center of an analytic differential system is analytically reducible. We also study the centers for the Cherkas polynomial differential systems ẋ = y, ẏ = P0(x) + P1(x)y + P2(x)y , where Pi(x) are polynomials of degree n, P0(0) = 0 and P ′ 0(0) < 0. Computing the focal values we find the center co...

Generic Interfaces for Transformation Systems