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Superspreading Events Without Superspreaders

Superspreading Events Without Superspreaders

October 26, 2020

Is a study posted on medRxiv, Prof. Mara Prentiss and two former Harvard physics students, Arthur Chu and Karl Berggren (MIT), analyzed transmission of COVID-19 using five well-documented case studies: a Washington state church choir, a Korean call center, a Korean exercise class, and two different Chinese bus trips. In all cases the likely index patients were pre-symptomatic or mildly symptomatic, which is when infective patients are most likely to interact with large groups of people. An estimate of N0, the characteristic number of COVID-19 virions needed to...

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Probing light-driven quantum materials with ultrafast resonant inelastic X-ray scattering

Probing light-driven quantum materials with ultrafast resonant inelastic X-ray scattering

October 19, 2020

Ultrafast optical pulses are an increasingly important tool for controlling quantum materials and triggering novel photo-induced phase transitions. Understanding these dynamic phenomena requires a probe sensitive to spin, charge, and orbital degrees of freedom. Time-resolved resonant inelastic X-ray scattering (trRIXS) is an emerging spectroscopic method, which responds to this need by providing unprecedented access to the finite-momentum fluctuation spectrum of photoexcited solids. In the latest issue of Communication Physics, Profs. Matteo Mitrano (Harvard) and Yao Wang (...

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QSC logo

Quantum Science Center: A Partnership to Drive the the Development of New Quantum Technologies

August 26, 2020

Professors Amir Yacoby and Prineha Narang (SEAS) have partnered with 15 institutions across the national lab, academia, and private industry landscapes to realize the potential of quantum information science through the establishment of the Quantum Science Center. 

Transforming the nation’s ability to innovate and, in turn, drive its economy in the 21st century requires revolutionary approaches to computing and sensing. In order to accelerate innovation, we need new technologies to accurately predict, detect, and model the complex world around us in areas such...

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Imaging Viscous Flow of the Dirac Fluid in Graphene

Imaging Viscous Flow of the Dirac Fluid in Graphene

July 23, 2020

It sounds like pure sorcery: using diamonds to observe invisible power swirling and flowing through carefully crafted channels. But these diamonds are a reality. [Harvard Physics Associate Mark J. H. Ku, and postdoc Tony Zhou, together with other members of Prof. Amir Yacoby's group, JQI Fellow Ronald Walsworth, and colleagues from several other institutions], have developed a way to use diamonds to see the elusive details of electrical currents.

The new technique gives researchers a map of the intricate movement of electricity in the microscopic world. The...

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Fig. 1a: chematic of TDBG with a twist angle θ.

Tunable Spin-Polarized Correlated States in Twisted Double Bilayer Graphene

July 9, 2020

Reducing the energy bandwidth of electrons in a lattice below the long-range Coulomb interaction energy promotes correlation effects. Moiré superlattices—which are created by stacking van der Waals heterostructures with a controlled twist angle—enable the engineering of electron band structure. Exotic quantum phases can emerge in an engineered moiré flat band. The recent discovery of correlated insulator states, superconductivity and the quantum anomalous Hall effect in the flat band of magic-angle twisted bilayer graphene has sparked the exploration of correlated electron states in...

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Forming a Single Molecule in an Optical Tweezer (artist's representation)

Longer Lived Molecules

July 1, 2020

Individual molecules placed in precisely defined quantum states could provide the building blocks for molecular arrays for quantum computing applications. But first, researchers need to develop techniques for creating these molecules. Now Jessie Zhang at Harvard University and colleagues demonstrate such a technique for forming a long-lived single NaCs molecule in a specific, reversible quantum state...

Continue reading "Longer Lived Molecules" by...

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Shut Down STEM poster

Towards a More Inclusive Physics Community

June 14, 2020

On June 10, 2020, the Department held a special department-wide meeting of the Equity & Inclusion Committee for a discussion focusing on how we can increase the number of African American physicists. Introductory comments by Department Chair, Prof. Subir Sachdev, are below.

Dear all,

I would like to make some personal remarks to mark the deaths of George Floyd, Ahmaud Arbery, Breonna Taylor, and many others, and recent national events.

I grew up in India and have spent my adult life in America. India and America have much in...

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Vafa book cover

"Puzzles to Unravel the Universe" -- New Book by Prof. Cumrun Vafa

June 12, 2020

Beneath all of the complex and formidable mathematical structures that formulate physical laws rest simple but deep nuggets of truth. It is these simple truths, and not the complicated technical details, that scientists strive for when uncovering the laws of nature. Fortunately, these core ideas can often be illustrated with simple mathematical puzzles. These puzzles are so simplified that one can tackle them and appreciate their meaning without using any complicated math. 

A new book by Prof. Cumrun Vafa, Puzzles to Unravel the Universe, aims to take the reader...

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