Paritosh Verma

Date: 12.10.2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

Grzegorz Pietrzyński

Date: 18.05.2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

I will discuss the most important problems related to distance determination with classical Cepheids and our current capabilities of using these stars to calibrate SN Ia and as the result to determine the Hubble constant. I will also comment on the role of classical Cepheids in the process  of studying one of the most important  problem in the history of science - the Hubble tension.

Bradley Cownden

Date: 26.04.2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26.04.2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26.04.2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Grzegorz Pietrzyński

Date: 18. 05. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

I will discuss the most important problems related to distance determination with classical Cepheids and our current capabilities of using these stars to calibrate SN Ia and as the result to determine the Hubble constant. I will also comment on the role of classical Cepheids in the process  of studying one of the most important  problem in the history of science - the Hubble tension.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Andrzej Odrzywołek

Date: 19. 10. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

Paritosh Verma

Date: 12. 10. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

Grzegorz Pietrzyński

Date: 18. 05. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

I will discuss the most important problems related to distance determination with classical Cepheids and our current capabilities of using these stars to calibrate SN Ia and as the result to determine the Hubble constant. I will also comment on the role of classical Cepheids in the process  of studying one of the most important  problem in the history of science - the Hubble tension.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.

Bradley Cownden

Date: 26. 04. 2022

Start Time: 10:15

Place: D-2-02

Organiser: ZTWiA

The quasinormal modes (QNMs) of a system, i.e. the exponentially damped, oscillatory solutions to linear wave equations, encode fundamental information about the system being studied. A familiar example is the spectroscopic analysis of QNMs of coalescing black hole binaries, which is used to obtain information about the mass and spin of the final state. The question of whether QNMs are stable or unstable under small perturbations is answered by the pseudospectrum. In this talk we discuss ongoing work into the examination of the pseudospectrum of the equivariant Yang-Mills soliton in (4+1)-dimensions. We discuss the hyperboloidal compactifications that allow us to determine the QNMs of the soliton not by the imposition of boundary conditions, but rather by appropriate regularity conditions on the solution. We then introduce the notion of the pseudospectrum and how it can be used to examine the stability of the QNMs under different types of perturbations. Finally, we contrast the spectral stability of solitons with what is already known about the spectral stability of Schwarzschild and Reissner-Nordstrom black holes.