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Fri 09 May 13:00: TBC

Upcoming talks - Tue, 29/04/2025 - 12:34
TBC

Abstract not available

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Fri 06 Jun 13:00: A Spacetime Interpretation of the Confluent Heun Functions in Black Hole Perturbation Theory

Upcoming talks - Tue, 29/04/2025 - 12:32
A Spacetime Interpretation of the Confluent Heun Functions in Black Hole Perturbation Theory

In Black Hole Perturbation Theory, confluent Heun functions appear as solutions to the radial Teukolsky equation, which governs perturbations in black hole spacetimes. While these functions are typically studied for their analytic properties, their connection to the underlying spacetime geometry has received less attention. In this talk, I will propose a spacetime interpretation of the confluent Heun functions, demonstrating how their behaviour near their singular points reflects the structure of key surfaces in Kerr spacetimes. By interpreting homotopic transformations of these functions as changes in the spacetime foliation, I will establish a connection between these solutions and various regions of the black hole’s global structure. I will also explore their relationship with the hyperboloidal formulation of the radial Teukolsky equation.

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Fri 30 May 13:00: Gravitational Wave Signatures of Dark Matter in Neutron Star Mergers

Upcoming talks - Mon, 28/04/2025 - 19:30
Gravitational Wave Signatures of Dark Matter in Neutron Star Mergers

Binary neutron star mergers provide insights into strong-field gravity and the properties of ultra-dense nuclear matter. These events offer the potential to search for signatures of physics beyond the standard model, including dark matter. We present the first numerical-relativity simulations of binary neutron star mergers admixed with dark matter, based on constraint-solved initial data. Modeling dark matter as a non-interacting fermionic gas, we investigate the impact of varying dark matter fractions and particle masses on the merger dynamics, ejecta mass, post-merger remnant properties, and the emitted gravitational waves. Our simulations suggest that the dark matter morphology – a dense core or a diluted halo – may alter the merger outcome. Scenarios with a dark matter core tend to exhibit a higher probability of prompt collapse, while those with a dark matter halo develop a common envelope, embedding the whole binary. Furthermore, gravitational wave signals from mergers with dark matter halo configurations exhibit significant deviations from standard models when the tidal deformability is calculated in a two-fluid framework neglecting the dilute and extended nature of the halo. This highlights the need for refined models in calculating the tidal deformability when considering mergers with extended dark matter structures. These initial results provide a basis for further exploration of dark matter’s role in binary neutron star mergers and their associated gravitational wave emission and can serve as a benchmark for future observations from advanced detectors and multi-messenger astrophysics.

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Fri 09 May 11:30: How do the most luminous black holes accrete and expel gas?

Upcoming talks - Mon, 28/04/2025 - 15:16
How do the most luminous black holes accrete and expel gas?

The gravitational pull of a black hole attracts gas and forms an accretion disk where the interplay between hydromagnetic processes and the warping of space-time releases gravitational energy in the form of radiation, relativistic jets, and winds. Most gas falls into supermassive black holes when the accretion rate approaches the Eddington limit (L=Ledd), at which point radiation pressure overcomes gravity. To date, our knowledge of such `luminous’ black hole accretion disks mostly relies on semi-analytical models, supplemented by a limited set of numerical simulations. In my talk I will discuss new insights gained from state-of-the-art radiative general relativistic magnetohydrodynamics (GRMHD) simulations of accretion near the Eddington limit such as the formation of a hot corona, disk truncation, and other physical processes driving the spectral evolution of luminous black holes. I will finish my talk by discussing the challenges and opportunities the next-generation of GRMHD simulations will bring in developing a comprehensive understanding of black hole accretion across the luminosity spectrum.

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Fri 02 May 13:00: The Black Hole Threshold

Upcoming talks - Mon, 28/04/2025 - 12:16
The Black Hole Threshold

Numerical evolutions show that, in spherical symmetry, as we move through the solution space of GR to the threshold of black hole formation, the resulting spacetimes tend to display a surprising degree of simplicity. A heuristic description of this behavior, called critical collapse, has been built around this empirical fact. Less is known when symmetry is dropped. In this presentation I will review the current status of the topic, focusing in particular on the struggle to understand the situation in axisymmetry.

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Thu 01 May 16:00: Irradiated brown dwarfs

Upcoming talks - Mon, 28/04/2025 - 11:25
Irradiated brown dwarfs

Brown dwarfs are often described as failed stars, however the flip side of this description is that they can also be described as over-ambitious planets. With masses between 13-70 Jupiter masses they have cool atmospheres dominated by cloud features, molecules and show features due to weather. These atmospheres have a lot of similarities with atmospheres we see in planets in our solar system, and also directly imaged exoplanets. The question then is: How like hot Jupiters are irradiated brown dwarfs? In this seminar I will describe the known irradiated brown dwarfs and how they evolve into post-common envelope systems containing a white dwarf. These rare binaries have very short periods (~hrs) and the brown dwarf is irradiated by the white dwarf companion, often with large amounts of UV radiation. I will discuss the atmospheres of these highly irradiated brown dwarfs and their similarities with irradiated exoplanets.

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Fri 20 Jun 13:00: TBC

Upcoming talks - Sat, 26/04/2025 - 13:44
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Fri 30 May 13:00: TBC

Upcoming talks - Sat, 26/04/2025 - 13:42
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Fri 16 May 13:00: TBC

Upcoming talks - Sat, 26/04/2025 - 13:41
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Fri 09 May 13:00: TBC

Upcoming talks - Sat, 26/04/2025 - 13:40
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Mon 16 Jun 14:00: Title to be confirmed

Upcoming talks - Fri, 25/04/2025 - 10:30
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Thu 05 Jun 14:00: Title to be confirmed

Upcoming talks - Fri, 25/04/2025 - 10:28
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Mon 02 Jun 14:00: Title to be confirmed

Upcoming talks - Fri, 25/04/2025 - 10:24
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Mon 12 May 14:00: Title to be confirmed

Upcoming talks - Fri, 25/04/2025 - 10:22
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Mon 19 May 14:00: Title to be confirmed

Upcoming talks - Fri, 25/04/2025 - 10:22
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Tue 27 May 14:00: Title to be confirmed

Upcoming talks - Fri, 25/04/2025 - 10:21
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Thu 29 May 14:00: Title to be confirmed

Upcoming talks - Fri, 25/04/2025 - 10:21
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Tue 29 Apr 13:00: Formation of planetary cores in spontaneously generated dust traps during the secular evolution of magnetized protoplanetary disks

None - Fri, 25/04/2025 - 03:32
Formation of planetary cores in spontaneously generated dust traps during the secular evolution of magnetized protoplanetary disks

An outstanding gap in the current planet formation theory is about the first steps of the planet formation process; namely how, when and where the initially ISM like solid dust particles grow into pebbles and planetesimals, the building blocks of planetary cores. Protoplanetary disks provide the initial conditions for the planet formation process. They are weakly magnetized accretion disks that are subject to the magnetorotational instability (MRI), one of the main magnetized processes responsible for their angular momentum transport and gas turbulence. The nonideal magnetohydrodynamic (MHD) effects prevent the MRI from operating everywhere in PPDs, leading to a complex dichotomy between MRI active regions with higher gas turbulence and non-MRI regions with lower gas turbulence. In this talk,  I will present the first numerical framework that describes the evolution of PPDs over millions of years powered by the MRI . It captures the MRI driven gas evolution via nonideal MHD calculations, which accounts for the dynamics and growth of the solid dust particles. An MRI powered mechanism that can spontaneously generate short- and long-lived pressure maxima in the PPD is unveiled. Within the long-lived pressure maxima, solid dust particles can be efficiently trapped, grow into pebbles, and reach high enough dust-to-gas mass ratios to potentially trigger the formation of planetesimals via the streaming instability. These planetesimals and pebbles can further rapidly interact to form planetary cores.

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Tue 29 Apr 13:00: Formation of planetary cores in spontaneously generated dust traps during the secular evolution of magnetized protoplanetary disks

Upcoming talks - Fri, 25/04/2025 - 03:32
Formation of planetary cores in spontaneously generated dust traps during the secular evolution of magnetized protoplanetary disks

An outstanding gap in the current planet formation theory is about the first steps of the planet formation process; namely how, when and where the initially ISM like solid dust particles grow into pebbles and planetesimals, the building blocks of planetary cores. Protoplanetary disks provide the initial conditions for the planet formation process. They are weakly magnetized accretion disks that are subject to the magnetorotational instability (MRI), one of the main magnetized processes responsible for their angular momentum transport and gas turbulence. The nonideal magnetohydrodynamic (MHD) effects prevent the MRI from operating everywhere in PPDs, leading to a complex dichotomy between MRI active regions with higher gas turbulence and non-MRI regions with lower gas turbulence. In this talk,  I will present the first numerical framework that describes the evolution of PPDs over millions of years powered by the MRI . It captures the MRI driven gas evolution via nonideal MHD calculations, which accounts for the dynamics and growth of the solid dust particles. An MRI powered mechanism that can spontaneously generate short- and long-lived pressure maxima in the PPD is unveiled. Within the long-lived pressure maxima, solid dust particles can be efficiently trapped, grow into pebbles, and reach high enough dust-to-gas mass ratios to potentially trigger the formation of planetesimals via the streaming instability. These planetesimals and pebbles can further rapidly interact to form planetary cores.

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Marie Curie Research Fellow (Fixed Term)

Department of Physics Jobs - Fri, 25/04/2025 - 01:00

We are seeking applicants for a PhD Fellowship in the framework of the MSCA Doctoral Network MASAUTO: MAterials for Smarter AUTOnomous sensors. MASAUTO is a research and training program for 12 Doctoral Candidates (DCs), focusing on developing a new generation of materials that will overcome the current bottlenecks in the capability and capacity of autonomous sensors. The ongoing exponential growth of the internet of things (IoT) ecosystem - which could reach a trillion devices in the near future - poses a serious challenge in terms of powering and interconnecting the underlying devices. The full potential of the IoT will only be achievable if devices i) have a reliable and sustainable autonomous power supply, and ii) are capable of processing information with reduced power requirements. A promising approach to address the first challenge is the use of an energy harvester-supercapacitor combination, while for the second challenge a promising strategy is the use of non-volatile random-access memories. It is, therefore, crucial to develop materials for energy harvesting and storage, as well as low power electronics. The overarching aim of the network is to position Europe as a leader in autonomous sensors for smart healthcare, industry and agriculture. More details can be viewed here: https://euraxess.ec.europa.eu/jobs/327706

Graduates of MASAUTO will be well-prepared for a career in as well as outside academia with an innovative and beyond state-of-the-art view on different aspects of materials and device development for smart sensors applications. MASAUTO offers DCs unique exciting opportunities, including:

• A project as a Marie Sklodowska Curie trainee in one of the participating institutions with the objective of becoming an experienced researcher and obtaining a doctoral degree (PhD);

• State-of-the art, exciting research in an international consortium with highly integrated projects;

• Solid multidisciplinary scientific training, from basic science to industrial applications, along with a complementary training in transferable skills, such as communication, entrepreneurship, intellectual property rights and ethics;

• A research training period in another consortium member's lab, performed in a different country;

• Gross Salary according to EU guidelines for Marie Sklodowska Curie trainees, including mobility payments and family allowances where applicable. The salary consists of the gross Monthly Living Allowance of 3.400,00 EUR per month pondered by the EU correction coefficient (specific for the countries where the hosting Institutions are located). In addition, a Mobility Allowance of 600,00 EUR per month will be paid, and also possibly another 660,00 EUR per month of Family Allowance depending on marital status. The DC salary is subject to local tax, employee and employer social contributions, and other deductions following national regulations.

The Fellowship is offered in conjunction with a PhD position, subject to the Fellow satisfying the University's admissions requirements for PhD study, and candidates should submit a formal application to the University of Cambridge for a PhD in Physics. The deadline for this is 16th May 2025.

The successful candidate will have an MSc degree in Physics, Chemistry or related field. You will also have outstanding academic records, and excellent communication skills in oral and written English.

Please ensure your application includes your CV, a list of grades/diplomas, a copy of the certificate for your highest qualification, and the contact details for at least two referees. You should also include a cover letter detailing your reasons for applying.

Applications received after the closing date will not be considered.

Fixed-term: The funds for this post are available for 36 months in the first instance.

Click the 'Apply' button below to register an account with our recruitment system (if you have not already) and apply online.

Informal enquiries are welcomed and should be directed to Professor Akshay Rao at ar525@cam.ac.uk. Please start the subject line with MASAUTO _QR

Please quote reference KA45807 on your application and in any correspondence about this vacancy.

The University actively supports equality, diversity and inclusion and encourages applications from all sections of society.

The University has a responsibility to ensure that all employees are eligible to live and work in the UK.

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