A continuous $p$-adic action on the $K(2)$-local algebraic $K$-theory of $p$-adic complex $K$-theory

TL;DR

This paper constructs a continuous $p$-adic action on the $K(2)$-local algebraic $K$-theory of $p$-adic complex $K$-theory, providing explicit fixed point spectra and spectral sequences relevant to a conjecture by Ausoni and Rognes.

Contribution

It offers an elementary construction of the homotopy fixed point spectrum for the $p$-adic action on $K(KU_p)$ and establishes a strongly convergent spectral sequence with specific properties.

Findings

Construction of the continuous homotopy fixed point spectrum for $p eq 2$

Spectral sequence with $E_2$-term given by Jannsen's continuous group cohomology

Vanishing of higher cohomology groups for $s > 2$

Abstract

Let $p$ be a prime, let $KU_p$ be $p$-complete complex $K$-theory, and let $\mathbb{Z}_p^\times$ denote the group of units in the $p$-adic integers. The $p$-adic Adams operations induce an action of the profinite group $\mathbb{Z}_p^\times$ on $KU_p$, and hence, on the algebraic $K$-theory spectrum $K(KU_p)$. For $p \geq 5$, we give an elementary construction of the continuous homotopy fixed point spectrum $(L_{K(2)}K(KU_p))^{hG}$, where $K(2)$ is the second Morava $K$-theory and $G$ is any closed subgroup of $\mathbb{Z}_p^\times$. Also, for each $G$, we show that there is an associated strongly convergent homotopy fixed point spectral sequence whose $E_2$-term is given by Jannsen's continuous group cohomology, with $E_2^{s,\ast} = 0$, for all $s > 2$. This work is related to a conjecture of Ausoni and Rognes.