arXiv subjects
Publications and source records attributed to Shengbo Zhao.
In this paper, we investigate large values of Dirichlet polynomials with multiplicative coefficients $\sum_{n\le N}f(n)n^{it}$, where $1\ll t\le T$ for large $T$. We prove an improved Omega result in the region $\exp((\log T)^{\frac12+\varepsilon})\le N\le\sqrt T$, where $T$ is large. We also show an Omega result when $\log N$ is around $\sqrt{\log T\log_2T}$.
In this article, we study extreme values of quadratic character sums with multiplicative coefficients $\sum_{n \le N}f(n)χ_d(n)$. For a positive number $N$ within a suitable range, we employ the resonance method to establish a conditional $Ω$-result.
In this paper, we investigate the conditional large values of the quadratic Dirichlet $L$-functions near the central point $s=1/2$. When $σ$ closes to $1/2$ within a suitable range, we show that $L(σ, χ_d)$ have the conditional large values of the similar order of magnitude as $L(1/2, χ_d)$.
In this article, we investigate large values of Dirichlet character sums with multiplicative coefficients $\sum_{n\le N}f(n)χ(n)$. We prove an Omega result in the region $\exp((\log q)^{\frac12+\varepsilon})\le N\le\sqrt q$, where $q$ is the prime modulus.
We establish an omega theorem for logarithmic derivative of the Riemann zeta function near the 1-line by resonance method. We show that the inequality $\left| ζ^{\prime}\left(σ_A+it\right)/ζ\left(σ_A+it\right) \right| \geqslant \left(\left(e^A-1\right)/A\right)\log_2 T + O\left(\log_2 T / \log_3 T\right)$ has a solution $t \in [T^β, T]$ for all sufficiently large $T,$ where $σ_A = 1 - A / \log_2 {T}.$Furthermore, we give a conditional lower bound for the measure of the set of $t$ for which the logarithmic derivative of the Riemann zeta function is large. Moreover, similar results can be generalized to Dirichlet $L$-functions.