People: Simone Colombo

Postdoctoral Fellow
Thu February 3, 2022

Reversing time for quantum-enhanced metrology

The group of Prof. Vuletic, at MIT, demonstrated that reversing the time in an atomic sensor can lead to a strongly enhanced sensitivity. With this time-reversal protocol, sensors can be operated with highly-entangled states which carry large statistical information close to the fundamental Heisenberg Limit.  Due to their fragility, these “superior” quantum states are extremely...
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Sun June 7, 2020

Entanglement-based Optical Atomic Clock beats the Standard Quantum Limit

Optical lattice clocks (OLC) are widely recognized as the next golden standard for timekeeping. Over the past decades, researchers around the world have made the second the best characterized among all seven of International System of Units (SI units), reaching an unprecedented fractional stability at few parts-of-ten-Quintillion (1019). Despite the tremendous effort of improving technology...
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Thu May 9, 2019

Near Unitary Squeezing

A group at the MIT led by Prof. Vladan Vuletić has recently generated significant amount of spin squeezing-a type of quantum entanglement-in an ultracold vapor of ytterbium-171. Spin squeezed states (SSS) can be used to overcome the standard quantum limit (SQL) which bounds state-of-the-art atomic sensors like optical clocks. The latter deploy a dilute vapor...
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Mon April 22, 2019

Direct Laser Cooling Rubidium Atoms

A group at MIT led by Vladan Vuletic has recently created a Bose-Einstein Condensate (BEC) of rubidium atoms with a new method, direct laser cooling. Many researchers have attempted this elusive goal in the past, but due to various complications resorted to reaching BEC through evaporation instead. Compared to cooling through evaporation, laser cooling is...
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Past Events
Fri April 19, 2019 2:00 pm
Location:MIT 26-210 and 26-214
Join CUA members to learn hands-on about some of the research that goes on in the CUA! Activities include a gum-drop model Ion Trap, a 6-foot Tornado Simulator, experiments with Liquid Nitrogen to see how ultracold temperatures change everyday objects, and a station to make your own holograms. The event will kick off with a...
Tue February 23, 2021 4:00 pm

CUA Virtual Seminar – Approaching the Heisenberg Limit with a time-reversal Hamiltonian


The creation of exotic quantum states that allow atomic sensors to operate beyond the Standard Quantum Limit (SQL) and near (or at) the Heisenberg Limit for many-particle systems has been a long-sought goal in Quantum Metrology. Gaussian Spin Squeezed States have been used to overcome the SQL in atomic sensors but offer limited quantum metrological advantages. To approach the Heisenberg Limit, Non-Gaussian Entangled States (NGES) with larger entanglement have to be engineered. However, the fragility of highly entangled states against decoherence and single-particle state resolution requirements have made difficult their experimental realization and application to atomic sensors with today’s technology.
We present here the implementation of a robust Signal Amplification through Time-reversal INteraction (SATIN) protocol, that allows for the generation of NGESs and the efficient use of their quantum resource. We demonstrate an angular resolution of 12.8 dB beyond the SQL for a system of 370 ytterbium-171 atoms (and 12.8 dB away from the Heisenberg limit), Heisenberg scaling with atom number, and a record-breaking phase-sensitive measurement of 11.8 dB beyond the SQL. We plan to transfer these NGESs to the optical-clock transition of ytterbium-171.

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