Skip to main content
Cornell University
LASSP -  Laboratory of Atomic and Solid State Physics

Cornell Laboratory for Atomic and Solid State Physics


RSS Feed

Dr Mohammad Hamidian wins the Lee Osheroff Richardson Science Prize

Early in his PhD at Cornell University (Ithaca, NY, USA), Dr Hamidian took on the challenge of developing an ultra-low vibration milliKelvin stage based upon an Oxford Instruments custom-designed version of the Kelvinox®400 dilution refrigerator. He designed and constructed a novel STM scanning head for that environment, devised a complete change of protocol for STM control and operation at milliKelvin temperatures, and enhanced the control of the dilution refrigerator itself to suppress vibration to many orders of magnitude below a commercially achievable scale. This system was the first successful milliKelvin spectroscopic imaging STM in the world and remains among only a handful in existence.


Cornell Chronicle

Dr. Mohammad Hamidian's Website


Dr Hamidian - 2016 Lee Osheroff Richardson Science Prize Winner

Gruner and Sethna part group that developes the first self-assembled superconductor

Sol Gruner and James Sethna are part of a collaboration that has created the first self-assembled, three-dimensional gyroidal superconductor. The gyroid is a complex cubic structure based on a surface that divides space into two separate volumes that are interpenetrating and contain various spirals. Pores and the superconducting material have structural dimensions of only around 10 nanometers, which could lead to entirely novel property profiles of superconductors.

Read more in:


self assembled superconductor

Ryan Badman joins grad student amadassadors engaging kids in nanotech

Ryan Badman has joined with other grad students in physics and engineering to engage school kids in nanoscience as part of the Cornell NanoScale Science and Technology Facility.

See the full article in the Chronicle.


CNF nanotech demonstration - Lindsay France/University Photography

Cohen group reveals the secret of the Oobleck

Neil Lin and Itai Cohen, along with researchers from the University of Edinburgh, have come up with a unique experiment to explain why shear thickening happens.

Read more in the Chronicle or the Synopsis or the full article in Physical Review Letters.

Shear thickening

Vengalattore group demonstrates "Weeping Angel" effect

The act of observation has profound consequences on a quantum system. In this work, we experimentally demonstrate the famous 'Heisenberg microscope' and show the dramatic effect of continuous position measurements on the evolution of a quantum system. In particular, we confine nanoKelvin temperature atoms within an optical lattice and show that the act of imaging these atoms induces their localization, i.e. suppresses tunneling. In other words, we freeze the quantum motion of these atoms simply by the act of gazing at them. This phenomenon, a manifestation of the quantum Zeno effect, has no classical equivalent. 

The nature of measurement and its influence on a quantum system presents one of the foremost puzzles in our current understanding of quantum physics. Its ramifications include the intrinsic obstacles to 'ideal' measurements, the origin of the so-called standard quantum limit to measurement precision and the incongruity of such concepts when extended to the macroscopic domain (as encapsulated, for instance, in Schrodinger's famous cat paradox). Our experiments distil the essence of a position measurement by observing the effect of single photon scattering events on the spatial evolution of an atom. Furthermore, the tunability and simplicity of our measurement technique potentially allows it to be used as a valuable resource for the control of interacting quantum many-body systems.

Our two-photon imaging technique also allows us to tune the 'strength of the measurement', i.e. the rate at which the atoms scatter photons, over a wide dynamic range. As we gradually increase this measurement strength, we observe the continuous crossover from the regime of weak measurements, where the act of observation has negligible influence on the atoms, to the regime of strong measurements, where the act of observation causes a dramatic suppression of tunneling. This crossover behavior is an instance of emergent classicality in a quantum system due to continuous measurement. 

More details

Popular Press -

QZE figure

Cohen group unravel root cause of plant twists and turns

To feed the world’s burgeoning population, producers must grow crops in more challenging terrain – where plant roots must cope with barriers. To that end, Tzer Han Tan, the Itai Cohen group and Boyce Thompson Institute plant biologists have uncovered a valuable plant root action, in that roots – when their downward path is blocked, as often occurs in rocky soil – display a “grow and switch” behavior, now reported in the latest Proceedings of the National Academy of Sciences. Prof Chris Henley, who passed away last June, also contributed to the research.

Read more in the Chronicle



plant root growth