arXiv subjects
Publications and source records attributed to Heng Du.
In this article, we relate any Farey triangle in the extended upper half-plane to a variant of Colmez--Fontaine's fundamental lemma in $p$-adic Hodge theory. In particular, their original fundamental lemma corresponds to the fundamental Farey triangle $(\frac{1}{0},\frac{1}{1},\frac{0}{1})$.
We prove that the relative p-adic monodromy theorem holds over a dense open subset. Moreover, we establish the equivalence of the following two statements: the local constancy of the Newton polygon function associated with a de Rham local system around rank-1 points, and the relative p-adic monodromy theorem near rank-1 points. We demonstrate how to extend the relative p-adic monodromy conjecture from the neighborhood of rank-1 points to the entire interiors of Newton partitions. Finally, we verify a conjecture of Howe-Klevdal concerning the potential good reduction of admissible pairs arising from variant of p-adic Hodge structures.
We show a comparison theorem between log prismatic cohomology and log crystalline cohomology for a $p$-adic formal scheme with semistable reduction. Combined with the prismatic-\'etale comparison theorem recently proved by Tian, this implies the $C_{\mathrm{st}}$-conjecture in the semistable case with coefficients given by semistable local systems.
We define the big crystalline site for a log scheme and prove the basic properties. In particular, we show the boundedness, base change, and perfectness theorems for the crystalline higher direct image of quasi-coherent crystals between fine log schemes. We also introduce the big absolute crystalline sites and discuss the Frobenius isogeny property of the crystalline higher direct image of $F$-isocrystals.
Our goal is to study $p$-adic local systems on a rigid-analytic variety with semistable formal model. We prove that such a local system is semistable if and only if so are its restrictions to the points corresponding to the irreducible components of the special fiber. For this, the main body of the paper concerns analytic prismatic $F$-crystals on the absolute logarithmic prismatic site of a semistable $p$-adic log formal scheme. Analyzing Breuil-Kisin log prisms, we obtain a prismatic purity theorem and deduce the above purity theorem for semistable local systems.
In this paper, we apply the theory of Bridgeland stability conditions, which was motivated by ideas from string theory, to study the derived category of coherent sheaves on Fargues--Fontaine curves. This leads us to consider the quasi-coherent sheaves $\mathcal{O}(\theta^{\pm})$ via the convergents of an irrational number $\theta$. We define the continuum envelope $\mathrm{QCoh}_{\mathbb{R}}(X{FF})$ to be the smallest abelian subcategory of $\mathrm{QCoh}(X_{FF})$ containing $\mathrm{Coh}(X_{FF})$ and $\mathcal{O}(\theta^{\pm})$. We study the homological algebra of $\mathrm{QCoh}_{\mathbb{R}}(X{FF})$ via Farey diagrams. We show that the homological properties of $\mathcal{O}(\theta^{\pm})$ depend heavily on the Diophantine properties of $\theta$. From this point of view, Fargues--Fontaine curves exhibit strong similarities to complex elliptic curves.
We show all Laurent $F$-crystals over $p$-adic fields are overconvergent.
We introduce the notion of completed $F$-crystals on the absolute prismatic site of a smooth $p$-adic formal scheme. We define a functor from the category of completed prismatic $F$-crystals to that of crystalline \'etale $\mathbf{Z}_p$-local systems on the generic fiber of the formal scheme and show that it gives an equivalence of categories. This generalizes the work of Bhatt and Scholze, which treats the case of a complete discrete valuation ring with perfect residue field.
We give a new construction of $(\varphi, \hat G)$-modules using the theory of prisms developed by Bhatt and Scholze. As an application, we give a new proof about the equivalence between the category of prismatic $F$-crystals in finite locally free $\mathcal{O}_\Delta$-modules over $(\mathcal{O}_K)_\Delta$ and the category of lattices in crystalline representations of $G_K$, where $K$ is a complete discretely valued field of mixed characteristic with perfect residue field. We also generalize this result to semi-stable representations using the absolute logarithmic prismatic site defined by Koshikawa.
Let $\mathcal{O}_E$ be a complete discrete valuation ring and $R$ be a perfect ring in characteristic $p$, we also assume $R$ is a complete valuation ring whose valuation group is of rank one and non-discrete, we prove the Krull dimension of the ring $W_{\mathcal{O}_E}(R)$ of $\mathcal{O}_E$-Witt vectors over $R$ is at least the cardinality of the continuum.
Let $K$ be a discrete valuation field with perfect residue field, we study the functor from weakly admissible filtered $(\varphi,N,G_K)$-modules over $K$ to the isogeny category of Breuil-Kisin-Fargues $G_K$-modules. This functor is the composition of a functor defined by Fargues-Fontaine from weakly admissible filtered $(\varphi,N,G_K)$-modules to $G_K$-equivariant modifications of vector bundles over the Fargues-Fontaine curve $X_{FF}$, with the functor of Fargues-Scholze that between the category of admissible modifications of vector bundles over $X_{FF}$ and the isogeny category of Breuil-Kisin-Fargues modules. We study those objects appear in the essential image of the above functor and call them arithmetic BKF modules. We show certain rigidity result of arithmetic BKF modules and use it to compare existing $p$-adic Hodge theories at ${A}_{\mathrm{inf}}$ level.
Laser cooling of relativistic heavy ion beams of Li-like C$^{3+}$ and O$^{4+}$ is being in preparation at the experimental Cooler Storage Ring (CSRe). Recently, a preparatory experiment to test important prerequisites for laser cooling of relativistic $^{12}$C$^{3+}$ ion beams using a pulsed laser system has been performed at the CSRe. Unfortunately, the interaction between the ions and the pulsed laser cannot be detected. In order to study the laser cooling process and find the optimized parameters for future laser cooling experiment, a multi-particle tracking method was developed to simulate the detailed longitudinal dynamics of laser-cooled ion beams at the CSRe. The simulations of laser cooling of the $^{12}$C$^{3+}$ ion beams by scanning the frequency of RF-buncher or continuous wave (CW) laser wavelength were performed. The simulation results indicated that a large momentum spread ion beams could be laser-cooled by the combination of only one CW laser and the RF-buncher and shown the requirements of a successful laser cooling experiment. The optimized parameters for scanning the RF-buncher frequency or laser frequency were obtained. Furthermore, the heating effects were estimated for laser cooling at the CSRe. The Schottky noise spectra of longitudinally modulated and laser-cooled ion beams was simulated to fully explain and anticipate the experimental results. The combination of Schottky spectra from the highly sensitive resonant Schottky pick-up and the simulation methods developed in this paper will be helpful to investigate the longitudinal dynamics of RF-bunched and ultra-cold ion beams in the upcoming laser cooling experiments at the CSRe.
A room temperature heavy ion linac has been proposed as a new injector of CSRm (the main Cooler Storage Ring) at HIRFL (Heavy Ion Research Facility in Lanzhou), which is expected to improve the performance of HIRFL. The linac injector can supply heavy ion with maximum mass to charge ratio of 7 and injection kinetic energy of 7.272MeV/u for CSRm, and the pulsed beam intensity is 3emA with the duty factor of 3%. Compared with the present cyclotron injector SFC (Sector Focusing Cyclotron), the beam current from linac can be improved by 10-100 times. As the pre-accelerator of the linac, the 108.48MHz 4-rod RFQ accelerates ion beam from 4keV/u to 300keV/u, which achieves the transmission efficiency of 95.3% with 3.07m long vanes. The phase advance has been taken into account to analysis the error tolerance, and parametric resonance have been carefully avoided by adjusting the structure parameters. KONUS IH-DTLs, which follow the RFQ, accelerate the ions up to the energy of 7.272MeV/u and inject into HIRFL-CSRm. The resonance frequency is 108.48MHz for the first two cavities and 216.96MHz for the last 5 DTLs. The maximum accelerating gradient can reach 4.95MV/m in DTL section with the length of 17.066m, and the total pulsed RF power is 2.8MW. A new strategy, for the determination of resonance frequency, RFQ vane voltage and DTL effective accelerating voltage, is described in detail. The beam dynamics design of the linac will be present in this paper.