elasticsearch query dates by range
Your field is a string, the format property is ignored. You should change your mapping and use the date type. Have a look here to see the core types available in elasticsearch.
I would use a filter instead of a query. It will be cached, thus faster. The following is an example for the last 7 days:
{ "filter" : { "range" : { "PublishTime" : { "from" : "20130505T000000", "to" : "20131105T235959" } } }}Note that if you use the filter like this it's going to be the same filter the whole day, thus you would make good use of the cache.