Do shards use separate processors on single node?

For general awareness, do separate shards on a single node use separate processors?
Do the shards use separate cores but only a single processor?
Is the behavior different between windows and linux?

I ask because when I start up a single-node, multi-shard instance on windows, I see only one new process in Task Manager. Even after executing a query, I don't see any more processes.

On linux, I see only a single process for a single-node, multi-shard instance.

There will be only one process per server. Each JVM instance runs multiple
threads per process, which are constrained by the thread pools:

The number of shards has no relevance on the number of threads. Each shard
is a separate Lucene index, but they are all managed by the cluster.