ELFT HÍRADÓ

[Andras Palyi <palyi AT mail.bme.hu>]

Dear Colleagues, 

Next Monday the BME Exotic Quantum Phases seminar continues with this talk:

  Alessandro Romito (Lancaster)
  Entanglement transition from continuous quantum measurements

Time: March 1, 14:15
Location: online in Teams
Abstract: see below

Teams link:
https://teams.microsoft.com/l/meetup-join/19%3a98c537f3ff3a433983cc04579e4603af%40thread.tacv2/1614339272371?context=%7b%22Tid%22%3a%226a3548ab-7570-4271-91a8-58da00697029%22%2c%22Oid%22%3a%22f8b27e90-dbca-4bb5-813c-d6415577ec35%22%7d

Best regards,
Andras Palyi 

= = = 
Abstract:

Quantum measurements can induce an entanglement transition between extensive 
and sub-extensive scaling of the entanglement entropy. This transition is of 
great interest since it illuminates the intricate physics of thermalization 
and control in open interacting quantum systems. Whilst this transition is 
well established for stroboscopic measurements in random quantum circuits, a 
crucial link to physical settings is its extension to continuous observations 
where, for an integrable model, it has been shown that a sub-extensive 
scaling appears for arbitrarily weak measurements.

In this talk, I present results for a one-dimensional quantum circuit 
evolving under random unitary transformations and generic positive 
operator-valued measurements of "variable strength". I will show that, for 
stroboscopic dynamics, there is a phase transition controlled by both the 
measurement density and the measurement strength. I will further show that 
the entanglement transition at a finite measurement strength persists for a 
continuously measured system with randomly non-integrable unitary evolution. 
I will finally present results for non-interacting models, in which a 
transition between logarithmic growth and strict localization of entanglement 
is still possible due to measurement induced dynamics. These results open the 
possibility to investigate the measurement induced entanglement transition in 
quantum architectures accessible via continuous measurements.