Department of Physics

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Information for students and staff about the coronavirus

The Swedish Public Health Agency has updated its risk assessment for spread of the corona virus. This is the policy for staff and students at the Department of Physics.

Professor Anders Nilsson

Stockholm University part in a billion investment in materials science

Stockholm University is one of six universities that will share SEK 2.7 billion within the new research program Wallenberg Initiative Material Science for Sustainability. The research that will take place at the Department of Materials and Environmental Chemistry. Professor Anders Nilsson will be the researcher at the Department of Physics.

Dr Magdalena Zych

27 new Wallenberg Academy Fellows appointed – over half are women

Knut and Alice Wallenberg Foundation has announced 27 new Wallenberg Academy Fellows. With the help of five years of funding. Among them is Dr Magdalena Zych and she will be at the Department of Physics. She's investigating how time flows in the quantum world.

How to reduce our carbon dioxid emission from travels?

That was the question we asked at a seminar for Fysikum employees 16 November 2021. Twenty four participated in the Zoom meeting. More than half of our emissions come from transports and travels and we focused on how to reduce flight travels that is the major part of the emissions.

Michael Gatchell, forskare på Fysikums avdelning för Atomfysik.

Coronene molecules contribute to complex chemistry in space

Carbon forms the basis of all organic chemistry and thus the building blocks of life. There is increasing evidence that amino acids and other complex organic molecules can be formed in space and spread to planets through, e.g., comet impacts. Large carbon-based molecule such as coronene could play an important role in how such organic molecules are produced in astronomical environments. Michael Gatchell has been interested in understanding the universe for as long as he can remember. Here he tells us about his research at Atomic Physics division of Fysikum and new results can change how we imagine molecules such as coronene contribute to chemistry in space.

Policy for meetings and travels

The purpose of this policy is to make all students and employees aware of the importance to plan their meetings and travels to minimice the environmental impact. The meeting is on November 16, 1:30-3:00 pm.

Sergey Koroidov, Researcher, The Department of Physics

Conversion of carbon dioxide back into fuels

The conversion of carbon dioxide back into fuels via electrochemistry is a very attractive alternative. - In my studies, I am developing the essential understanding of these reactions by following time-resolved transformation at the atomic and molecular level, says Sergey Koroidov.

Foto Ingmarie Andersson

Information about courses given during autumn semester 2021

The government and the public health authority have decided that the restrictions will be lifted on September 29 -2021. The president of Stockholm University has previously decided on a gradual return to campus teaching during the autumn semester (Dnr. SU- FV-1.1.2-1620-20). At the Department of Physics the format for teaching during the first half of the semester was decided June 4 -2021 (Dnr: SU-402-0072-21).

Optical Nano Cavities

Enhancing photophysical processes in molecules with attosecond pulse trains

Researchers at Fysikum have proposed a method, which uses ultrashort bursts of light, to gain deeper insight into complex photophysical processes of molecules occurring at femtosecond time scales. The proposed technique makes use of so-called attosecond pulse trains to track the motion of an excited molecule and its decay back to the ground state. During the measurement the molecule is ionized and the energy of the ejected electrons is recorded. The comb-like structure of the energy spectrum gives further insight into quantum mechanical processes that the excited molecules experiences.

Atomic Motion in Liquid Water Molecules

Importance of Quantum Effects in Water

Using ultrafast electron diffraction, Anders Nilsson at Stockholm University have participated in a study lead by colleagues at SLAC National Accelerator Laboratory in California on how the structure of water changes after a fast change in the quantum distribution of distances in the internal bond. Upon increasing the quantum number by one unit of the internal OH stretch the team surprisingly found that the hydrogen bond becomes strengthen. The finding is published this week in Nature.

Photon energy image. Credit Davide Bossini

Ultrafast light control of magnetism via the magnetoelastic effect

"One of the most exciting and least understood properties of materials is the so-called magnetoelasticity." Researcher Stefano Bonetti from the Department of Physics reports on experiments carried out in collaboration with universities in Germany, Japan and Italy.

Welcoming new students at fall 2021

Welcome to Fysikum - The Department of Physics!

During last week, we welcomed many new students to programs and courses at the Department of Physics. This year, the introductory meetings were given both on campus and remotely via zoom.

Suvasthika Indrajit

Suvasthika Indrajith works in experimental physics with atomic and molecular ions at DESIREE

- I started here in January as a post-doc and I won the thesis prize this year from the Chemistry-Physics Division of the French Chemical Society (SCF) and the French Society of Physic (SFP).

David Degerman. Foto Niklas Björling

Measuring the chemical and physical properties of molecules

- I am a PhD student in Chemical Physics with a background in materials chemistry. My current research is on x-ray spectroscopy of thermal catalysts for CO and CO2 hydrogenation reactions. In short: me and my colleagues have built a new instrument (the technical term would be a "synchrotron endstation for high-pressure x-ray photoelectron spectroscopy") capable of measuring the chemical and physical properties of molecules involved in the reaction under more realistic reaction conditions, says David Degerman.

Sara Strandberg

Measuring the Higgs boson

All matter on Earth and in the universe is made up of elementary particles that have existed since just after the Big Bang. Wallenberg Scholar Sara Strandberg is studying how the particles interact with each other. She is using data from the LHC particle collider at CERN to learn more about the Higgs Boson and the part it plays in the Standard Model of particle physics.

Lars G.M. Pettersson

Stockholm University receives four ERC Advanced Grants

On 22 April the ERC announced the researchers who will receive Advanced Grants starting in 2021. There are 209 grantees from 14 European countries and seven grants go to Sweden. Four researchers work at the Stockholm University – making the university the most successful this year. Two of them work at the Department of Physics: Hiranya V. Peiris, Professor of Cosmoparticle Physics and Director of the Oskar Klein Centre and Lars G.M. Pettersson, Professor of Theoretical Chemical Physics.

 

Student som studerar vid dator. Ekvationer på tavla i bakgrunden.

Information about form of teaching

The government and the public health authority have decided that the restrictions will be lifted on September 29 -2021. The president of Stockholm University has previously decided on a gradual return to campus teaching during the autumn semester (Dnr. SU- FV-1.1.2-1620-20). At the Department of Physics the format for teaching during the first half of the semester was decided June 4 -2021 (Dnr: SU-402-0072-21).

Foto Ingmarie Andersson

Information about courses given during autumn semester 2021

The government and the public health authority have decided that the restrictions will be lifted on September 29 -2021. The president of Stockholm University has previously decided on a gradual return to campus teaching during the autumn semester (Dnr. SU- FV-1.1.2-1620-20). At the Department of Physics the format for teaching during the first half of the semester was decided June 4 -2021 (Dnr: SU-402-0072-21).

The top part of the figure illustrates the system where pyrrole embedded inside an optical cavity. The bottom part represents the ground and excited state potential energy surfaces of pyrrole along NH dissociation.

Optical nano cavities: a control knob for tuning photo-chemical reactions on a quantum level

Researchers at Fysikum have theoretically investigated the light activated hydrogen abstraction reaction of pyrrole in an optical nano cavity. The electronic excitation of pyrrole with UV light triggers the hydrogen detachment reaction along the NH bond. Their latest paper investigates how strong light-matter coupling of a tightly confined electromagnetic mode can be used to steer this reaction. The results suggest that the cavity can hugely influence the reaction efficiency and open up alternative reaction pathways.

Figure illustrates a glass containing two water liquids that have different densities surrounded in a cold environment.

Water’s Heat Capacity Becomes Extreme in Supercooled Conditions

Using x-ray lasers, researchers at Stockholm University have developed a new ultrafast calorimetry technique to measure the heat capacity (Cp) of water down to 228 K. The finding is that Cp increases dramatically below 240 K and reach a maximum at around 230 K indicating an extreme amount of entropy fluctuations. The results are consistent with existence of a critical point at temperatures around 210-215 K and at pressures 800-1000 bar. Their findings are published this week in the Proceedings of the National Academy (US).

Monitoring coherent light-matter

Monitoring coherent light-matter interaction in the strong-coupling limit

In a recently published article in Optics Communications, Themis Mavrogordatos, Fysikum, and Cristóbal Lledó, University College London (UCL), address the coherence of side-scattering in the driven dissipative Jaynes–Cummings (JC) model. They link atomic fluorescence to the multi-photon resonance operation of the JC oscillator and point to the differences from the scattered field of ordinary resonance fluorescence. They show that fluorescence uncovers the details of the cascaded process organizing multi-photon blockade.

Hiranya Peiris

Hiranya Peiris awarded by the Royal Astronomical Society

Hiranya Peiris, professor of cosmoparticle physics at the Department of Physics and director of the Oskar Klein Center, Stockholm University, has been awarded with the Eddington Medal 2021 by the Royal Astronomical Society for her ground-breaking exploration of the origins of the Universe.

Physics World top 10 breakthrough

Top 10 breakthrough of the year - research from Stockholm University noticed by Physics World

The article "Tracking the dynamics of an ideal quantum measurement" has among 550 new research papers been selected as a top 10 breakthrough of the year by Physics World. 

The impact of alkali metal cations on the OER activity.

Activity descriptors of nickel-iron oxygen evolution electrocatalysts in the presence of cations

The oxygen evolution reaction (OER) is a key process that enables the storage of renewable energies in the form of chemical fuels. Electrolyte alkali metal cations have been shown to modify the activity and reaction intermediates in OER; however, the exact mechanism was not understood – until recently.

Hiranya Peiris - Foto: Niklas Björling

Hiranya Peiris is awarded the Max Born Medal and Prize 2021

Hiranya Peiris receives the award for her outstanding contribution in cosmology, where she has created new interdisciplinary connections between cosmology and high-energy physics.

Figure illustrates a glass containing two water liquids that have different densities surrounded in a cold environment.

Two liquids of water exist

Using x-ray lasers, researchers at Stockholm University have been able to follow the transformation between two distinct different liquid states of water at around -63 Centigrade, both being made of H2O molecules. Even though the two liquids can only be studied under extreme conditions, their existence strongly influences many of waters unique properties in our daily life. Their findings are published in the journal Science.

Image credit: C. Lledó

Exploring the collective and individual channels of light-matter interaction

In two reports published this month, we investigate atomic emission and light-matter correlations in absorptive optical bistability. From a linearized treatment of quantum fluctuations we show a visible departure from classical behavior and propose an experimental setup to extract the otherwise hidden collective degree of freedom coupled to the intracavity field.

Två doktorander i skyddsglasögon utför experiment

Electron–spin dynamics studied on its natural time-scale

By using extremely short light pulses and coincidence technology, researchers from several Swedish universities have managed to follow the dynamic process when the electron's spin - its rotation around its own axis - controls how an atom absorbs light

Rotation, precession, and nutation in obliquity of a planet

Spin nutation in magnetic materials observed for the first time

For the first time, spin nutation in magnetic materials has been observed. The discovery could impact the way digital information is saved and lead to a faster, more compact and more energy-efficient technology.

First Results from Desiree

First research from DESIREE using merged-beams

The DESIREE facility, with its unique design of two storage rings with a common straight section was constructed in order to study reactions between pairs of oppositely charged atomic or molecular ions. The results of the first such experiment have recently been published.

Schematic diagram of the experimental setup GANDALPH. A beam of negative ions enter the vacuum chamber to the left ans is overlapped with a laser beam. The neutrals created in photodetachment continue to the right and hit the detector, and the negative ion beam is bent to hit the ion detector.

The rarest element on earth is studied in detail

Can the rarest element on earth, astatine, be used to treat tumors? A new study published in Nature Communications is the first to measure in detail the electron affinity of astatine that is relevant for development of targeted alpha therapy.

The schematic of the experiment used to capture the alignment of water molecules by the laser light.  By using X-ray lasers, scientists have seen that the water molecules can be aligned for a very short time, forming a liquid crystal. Water molecules that are in a low-density liquid (LDL – blue regions) are easier to align that those in a high density liquid (HDL – yellow regions).

X-rays indicate that water can behave like a liquid crystal

Scientists at Stockholm University have discovered that water can exhibit a similar behavior like a liquid crystal when illuminated with laser light. This effect originates by the alignment of water molecules, which exhibit a mixture of low- and high-density domains that are more or less prone to alignment. Can this discovery have future technological applications?

Photo XENON collaboration

Excess Events observed in Dark Matter Experiment

Scientists from the international XENON collaboration announced today that data from their XENON1T, the world's most sensitive dark matter experiment, show a surprising excess of events.