Talk@IFUSP, friday 19/10, 3pm, by Prof. Avi Pe’er

This friday, 19/10, at Auditório Norte 3pm, Prof. Avi Pe’er from Bar Ilan University, will give a talk on

The Speed Limit of Quantum Measurement (and what we can achieve if we break it…)

Abstract:
Homodyne measurement is a corner-stone of quantum optics. It measures the fundamental variables of quantum electrodynamics – the quadratures of light, which constitute the optical analog of position and momentum. Yet, standard homodyne, which is used to measure quadratures, suffers from a severe bandwidth limitation: While the bandwidth of optical states can easily span many THz, standard homodyne detection is inherently limited to the electrically accessible, MHz-to-GHz range, leaving a dramatic gap between the relevant optical phenomena and the measurement capability.
We recently demonstrated a fully parallel optical homodyne measurement across an arbitrary optical bandwidth, effectively lifting the bandwidth limitation completely 1. Using optical parametric amplification, which amplifies one quadrature while attenuating the other, we could measure quadrature squeezing simultaneously across a bandwidth of 55THz.
I will review the broad context of quantum measurement and will present our parametric homodyne method and results. I will then discuss two immediate applications of parametric homodyne: First, broadband Quantum Key Distribution, where many quantum channels of communication can be multiplexed over a single broadband squeezer and using a single homodyne device. Second, Squeezing-enhanced Raman spectroscopy, where the detection sensitivity can surpass the shot-noise limit with a nonlinear interferometry scheme.

• Yaakov Shaked, Yoad Michael, Rafi Vered, Leon Bello, Michael Rosenbluh and Avi Pe’er, “Lifting the Bandwidth limit of Optical Homodyne Measurement”, Nature Comm. 9, 609 (2018)

Location: Auditório Norte, IFUSP.
Date: 19/10/2018, 15:00 hs

Mini-course on quantum optics – Cecilia Cormick

Prof. Cecilia Cormick, from Nacional University of Cordoba will teach a graduate-level mini-course on quantum optics, between 12/11 and 14/11 @ IFUSP. Topics will include cavity QED,  trapped ions and ultra-cold atoms in optical lattices.

More details will be posted soon on http://www.fmt.if.usp.br/~gtlandi/

Anyone interested is more than welcome to join. Students can also gain credits by enrolling in the course.

Talk@IFUSP, Thursday, 11/10 at 10pm. Prof. Fernando Nicacio

Title:

Determining stationary-state quantum properties directly from system-environment interactions

Prof. Dr. Fernando Antonio Nazareth Nicacio

Universidade Federal do Rio de Janeiro, RJ

Considering stationary states of continuous-variable systems undergoing an open dynamics, we unveil the connection between properties and symmetries of the latter and the dynamical parameters. In particular, we explore the relation between the Lyapunov equation for dynamical systems and the steady-state solutions of a time-independent Lindblad master equation for bosonic modes. Exploiting bona fide relations that characterize some genuine quantum properties (entanglement, classicality, and steerability), we obtain conditions on the dynamical parameters for which the system is driven to a steady state possessing such properties. We also develop a method to capture the symmetries of a steady state based on symmetries of the Lyapunov equation. All the results and examples can be useful for steady-state engineering processes.

Data: 11 de outubro de 2018 (quinta-feira)
Horário: às 10h

Local: Sala de Seminários José Roberto Leite  – Edifício Alessandro Volta (bloco C)