An Optimal Inequality for One-Parameter Mean

An Optimal Double Inequality among the One-Parameter, Arithmetic and Geometric Means

In the present paper, we answer the question: for 0 1    fixed, what are the greatest value   p  and the least value   q  such that the double inequality           , , 1 , p q , J a b A a b G a b J a b       holds for all with ? where for , the one-parameter mean , 0 a b  a b  p R    , p J a b  , , arithmetic mean  A a b     and geometric mean of two positive...

Optimal Bounds for Seiffert Mean in terms of One-Parameter Means

Optimal One–parameter Mean Bounds for the Convex Combination of Arithmetic and Logarithmic Means

We find the greatest value p1 = p1(α) and the least value p2 = p2(α) such that the double inequality Jp1 (a,b) <αA(a,b)+(1−α)L(a,b) < Jp2 (a,b) holds for any α ∈ (0,1) and all a,b > 0 with a = b . Here, A(a,b) , L(a,b) and Jp(a,b) denote the arithmetic, logarithmic and p -th one-parameter means of two positive numbers a and b , respectively. Mathematics subject classification (2010): 26E60.

Optimal estimation of one parameter quantum channels

We explore the task of optimal quantum channel identification, and in particular the estimation of a general one parameter quantum process. We derive new characterizations of optimality and apply the results to several examples including the qubit depolarizing channel and the harmonic oscillator damping channel. We also discuss the geometry of the problem and illustrate the usefulness of using ...

An Optimal Double Inequality for Means

For p ∈ R, the generalized logarithmic mean Lp a, b , arithmetic mean A a, b and geometric mean G a, b of two positive numbers a and b are defined by Lp a, b a, a b; Lp a, b a 1 − b 1 / p 1 a − b , p / 0, p / − 1, a/ b; Lp a, b 1/e b/a 1/ b−a , p 0, a/ b; Lp a, b b − a / ln b − lna , p −1, a/ b; A a, b a b /2 and G a, b √ ab, respectively. In this paper, we give an answer to the open problem: f...