Zobrazeno 1 - 10
of 414
pro vyhledávání: '"Xu, Zixuan"'
We propose cosmological observations of Lyman-alpha and 21-cm signal to set stringent constraints on freeze-in dark matter (FIDM). Explicitly we consider Higgs (neutrino)-portal FIDM in the single-field context, which injects energy into the intergal
Externí odkaz:
http://arxiv.org/abs/2407.08225
We construct $n$-node graphs on which any $O(n)$-size spanner has additive error at least $+\Omega(n^{3/17})$, improving on the previous best lower bound of $\Omega(n^{1/7})$ [Bodwin-Hoppenworth FOCS '22]. Our construction completes the first two ste
Externí odkaz:
http://arxiv.org/abs/2404.18337
Autor:
Alman, Josh, Duan, Ran, Williams, Virginia Vassilevska, Xu, Yinzhan, Xu, Zixuan, Zhou, Renfei
We present a new improvement on the laser method for designing fast matrix multiplication algorithms. The new method further develops the recent advances by [Duan, Wu, Zhou FOCS 2023] and [Vassilevska Williams, Xu, Xu, Zhou SODA 2024]. Surprisingly t
Externí odkaz:
http://arxiv.org/abs/2404.16349
Roundtrip spanners are the analog of spanners in directed graphs, where the roundtrip metric is used as a notion of distance. Recent works have shown existential results of roundtrip spanners nearly matching the undirected case, but the time complexi
Externí odkaz:
http://arxiv.org/abs/2310.20473
We provide a variety of lower bounds for the well-known shortcut set problem: how much can one decrease the diameter of a directed graph on $n$ vertices and $m$ edges by adding $O(n)$ or $O(m)$ of shortcuts from the transitive closure of the graph. O
Externí odkaz:
http://arxiv.org/abs/2310.12051
Autor:
Sauermann, Lisa, Xu, Zixuan
We prove a new lower bound for the almost 20 year old problem of determining the smallest possible size of an essential cover of the $n$-dimensional hypercube $\{\pm 1\}^n$, i.e. the smallest possible size of a collection of hyperplanes that forms a
Externí odkaz:
http://arxiv.org/abs/2310.05775
The main contribution of this paper is a new improved variant of the laser method for designing matrix multiplication algorithms. Building upon the recent techniques of [Duan, Wu, Zhou, FOCS 2023], the new method introduces several new ingredients th
Externí odkaz:
http://arxiv.org/abs/2307.07970
The $k$-Detour problem is a basic path-finding problem: given a graph $G$ on $n$ vertices, with specified nodes $s$ and $t$, and a positive integer $k$, the goal is to determine if $G$ has an $st$-path of length exactly $\text{dist}(s, t) + k$, where
Externí odkaz:
http://arxiv.org/abs/2307.01781
Gravitational freeze-in is a mechanism to explain the observed dark matter relic density if dark matter neither couples to inflation nor to standard model sector. In this work, we study gravitational freeze-in dark matter production during Higgs preh
Externí odkaz:
http://arxiv.org/abs/2305.02568
We propose a new freeze-in dark matter candidate which feebly couples to the standard model charged leptons. The feeble interactions allow it (i) to freeze-in from the Standard Model thermal bath with its relic density being either a fraction or the
Externí odkaz:
http://arxiv.org/abs/2304.02904