Qubes OS uses Xen hypervisor for creating and isolating the virtual machines. We can work on these virtual machines to access the same application in isolation.

We can use two different instances of the same browser side by side, and they may be running on different security domains. If we visit a website using both the browsers, and are logged into the website on one if them, that login session will not be used by the other browser window, as it is running on a completely different virtual machine.