89,238 research outputs found
Subexponentially increasing sums of partial quotients in continued fraction expansions
We investigate from a multifractal analysis point of view the increasing rate
of the sums of partial quotients , where
is the continued fraction expansion of an
irrational . Precisely, for an increasing function , one is interested in the Hausdorff
dimension of the setsSeveral cases are solved by Iommi and
Jordan, Wu and Xu, and Xu. We attack the remaining subexponential case
. We show that when , has Hausdorff dimension . Thus, surprisingly, the
dimension has a jump from to at . In a
similar way, the distribution of the largest partial quotient is also studied.Comment: 12 pages. More details for the proof of Theorem 1.2. are adde
On two subgroups of U(n), important for quantum computing
ZU(n) and XU(n) are subgroups of the unitary group U(n): the group XU(n) consists of all n X n unitary matrices with all 2n line sums (i.e. all n row sums and all n column sums) equal to 1 and the group ZU(n) consists of all n X n unitary diagonal matrices with first entry equal to 1
SU(3)X SU(2)XU(1) Chiral Models from Intersecting D4-/D5-branes
We clarify RR tadpole cancellation conditions for intersecting D4-/D5-branes.
We find all of the D4-brane models which have D=4 three-generation chiral
fermions with the SU(3)XSU(2)XU(1)^n symmetries. For the D5-brane case, we
present a solution to the conditions which gives exactly the matter contents of
standard model with U(1) anomalies.Comment: 6 pages, submitted to Progress Letter
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