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Gravitational collider physics uses binary black hole mergers to probe ultralight bosons through their effect on gravitational waves. Bound boson fields form "gravitational atoms" around black holes that can undergo transitions when perturbed by an orbiting companion. This leads to distinctive signatures in the gravitational waves like floating or sinking orbits and sharp features in the frequency evolution. Ionization of the cloud can also significantly shorten the merger time. Precise waveform modeling is still needed to apply these effects in gravitational wave searches.

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Multiverse

This document discusses the multiverse theory in physics. It begins by defining the observable universe and the idea of a multiverse as multiple observable universes. It then covers evidence that led physicists to consider the multiverse, including the accelerating expansion of the universe and problems with the cosmological constant. It describes two versions of the multiverse theory - the inflationary multiverse from eternal inflation and the string theory landscape. It concludes by questioning whether the multiverse is a scientific theory and if it is testable or predictive.

The Scientific Legacy of Stephen Hawking

Stephen Hawking made several major contributions to our understanding of black holes and the Big Bang. He showed that black holes can emit radiation, causing them to evaporate over time. His work also linked black hole entropy to their surface area. For the Big Bang, Hawking proposed that inflation explained the early rapid expansion of the universe and the origin of cosmic structure. He also suggested that time had no boundary at the beginning of the universe and that quantum effects could have caused the universe and possibly others to spontaneously appear.

Caltech Physics Colloquium

Daniel Baumann presented work on developing a "cosmological bootstrap" approach to understand cosmological correlations. This approach focuses on directly constraining correlations on the boundary of de Sitter space using principles like locality, causality and symmetries. Correlators have singularities when energies are conserved that are analogous to scattering amplitudes. Symmetries relate these singularities to the physical regime, and if massive particles are present there will be oscillatory features reflecting their production and evolution. These oscillations could potentially be observed as signatures in future galaxy surveys, providing a way to study physics during inflation like a "cosmological collider".

Kitp 2022

The document discusses the connections between cosmology and fundamental physics, noting that cosmology is interconnected with theories of inflation, dark matter, quantum gravity, and more. It outlines strategies for improving models of inflation, large scale structure, and the late universe through both top-down and bottom-up approaches, emphasizing the use of principles like symmetries, effective field theory, and causality. Key observational probes discussed include the CMB, large scale structure, and gravitational waves.

Lectures on Cosmological Correlations

Slides of lectures presented at the Kavli Asian Winter School on Strings, Particles and Cosmology 2023, in Korea.

The Past, Present and Future of Cosmology

The document summarizes the past, present, and future of cosmology. It describes how observations of the cosmic microwave background have established a standard cosmological model involving dark matter, dark energy, and nearly scale-invariant primordial fluctuations from inflation. However, key questions remain about the nature of dark matter and dark energy, as well as the origin and dynamics of inflation. Ongoing and future CMB polarization experiments aim to detect primordial gravitational waves from inflation, which would provide strong evidence for inflation and insights into high-energy physics.

Introduction to Cosmology

This document provides an introduction to cosmology, outlining key concepts in three main areas: the expanding universe, structure formation, and the quantum origin of fluctuations. It begins by deriving the Friedmann equation governing the expansion of the universe and discussing how different components (matter, radiation, dark energy) evolve over time. It then explains how small primordial density fluctuations grew via gravitational clustering to form the large-scale structure we observe. Finally, it connects this structure formation to quantum fluctuations during an early period of cosmological inflation, which provided the seeds for all later structure.

The Big Bang and the Origin of Structure

The document discusses the Big Bang theory of the origin and evolution of the universe. It describes how observations show that the universe began in a hot, dense state around 13.8 billion years ago and has been expanding and cooling ever since. The earliest moments after the Big Bang are explained by a brief period of exponential expansion called inflation that seeded the initial fluctuations which later grew via gravity to form all observed structures. Future experiments aim to detect gravitational waves from inflation, which would provide strong evidence supporting this theory of cosmic origins.

Multiverse

This document discusses the multiverse theory in physics. It begins by defining the observable universe and the idea of a multiverse as multiple observable universes. It then covers evidence that led physicists to consider the multiverse, including the accelerating expansion of the universe and problems with the cosmological constant. It describes two versions of the multiverse theory - the inflationary multiverse from eternal inflation and the string theory landscape. It concludes by questioning whether the multiverse is a scientific theory and if it is testable or predictive.

The Scientific Legacy of Stephen Hawking

Stephen Hawking made several major contributions to our understanding of black holes and the Big Bang. He showed that black holes can emit radiation, causing them to evaporate over time. His work also linked black hole entropy to their surface area. For the Big Bang, Hawking proposed that inflation explained the early rapid expansion of the universe and the origin of cosmic structure. He also suggested that time had no boundary at the beginning of the universe and that quantum effects could have caused the universe and possibly others to spontaneously appear.

Caltech Physics Colloquium

Daniel Baumann presented work on developing a "cosmological bootstrap" approach to understand cosmological correlations. This approach focuses on directly constraining correlations on the boundary of de Sitter space using principles like locality, causality and symmetries. Correlators have singularities when energies are conserved that are analogous to scattering amplitudes. Symmetries relate these singularities to the physical regime, and if massive particles are present there will be oscillatory features reflecting their production and evolution. These oscillations could potentially be observed as signatures in future galaxy surveys, providing a way to study physics during inflation like a "cosmological collider".

Kitp 2022

The document discusses the connections between cosmology and fundamental physics, noting that cosmology is interconnected with theories of inflation, dark matter, quantum gravity, and more. It outlines strategies for improving models of inflation, large scale structure, and the late universe through both top-down and bottom-up approaches, emphasizing the use of principles like symmetries, effective field theory, and causality. Key observational probes discussed include the CMB, large scale structure, and gravitational waves.

Lectures on Cosmological Correlations

Slides of lectures presented at the Kavli Asian Winter School on Strings, Particles and Cosmology 2023, in Korea.

The Past, Present and Future of Cosmology

The document summarizes the past, present, and future of cosmology. It describes how observations of the cosmic microwave background have established a standard cosmological model involving dark matter, dark energy, and nearly scale-invariant primordial fluctuations from inflation. However, key questions remain about the nature of dark matter and dark energy, as well as the origin and dynamics of inflation. Ongoing and future CMB polarization experiments aim to detect primordial gravitational waves from inflation, which would provide strong evidence for inflation and insights into high-energy physics.

Introduction to Cosmology

This document provides an introduction to cosmology, outlining key concepts in three main areas: the expanding universe, structure formation, and the quantum origin of fluctuations. It begins by deriving the Friedmann equation governing the expansion of the universe and discussing how different components (matter, radiation, dark energy) evolve over time. It then explains how small primordial density fluctuations grew via gravitational clustering to form the large-scale structure we observe. Finally, it connects this structure formation to quantum fluctuations during an early period of cosmological inflation, which provided the seeds for all later structure.

The Big Bang and the Origin of Structure

The document discusses the Big Bang theory of the origin and evolution of the universe. It describes how observations show that the universe began in a hot, dense state around 13.8 billion years ago and has been expanding and cooling ever since. The earliest moments after the Big Bang are explained by a brief period of exponential expansion called inflation that seeded the initial fluctuations which later grew via gravity to form all observed structures. Future experiments aim to detect gravitational waves from inflation, which would provide strong evidence supporting this theory of cosmic origins.

Cosmology

This document discusses the relationship between amplitudes and cosmology. Amplitude methods have led to advances in computing cosmological correlations through recursion relations and generalized unitarity. Observations of the CMB and large-scale structure have revealed properties of the primordial fluctuations, including near scale-invariance, adiabaticity, and Gaussianity. Models of inflation aim to explain these properties, and the effective field theory of inflation provides a framework to study fluctuations beyond slow-roll. Future experiments will further probe the initial conditions and search for signatures of the ultraviolet completion of inflation such as non-Gaussianity and tensor modes.

On the Origin of Structure in the Universe

1) The talk discusses the origin of structure in the universe, from the small density fluctuations after the Big Bang to the galaxies, stars and planets we see today.
2) It explains how quantum fluctuations during an early period of exponential expansion called inflation were stretched to cosmological scales by inflation, seeding these initial density fluctuations.
3) The talk outlines how measurements of the cosmic microwave background have revealed correlations in the fluctuations that can only be explained by a period of inflation in the early universe that was faster than the speed of light.

Letting Go of Spacetime

A short talk on why quantum gravity should make us suspicious of locality as a fundamental principle of physics.

Many Worlds, the Born Rule, and Self-Locating Uncertainty

A semi-technical talk on deriving the Born Rule for quantum probabilities in the Everett (many-worlds) formulation of quantum mechanics.

What We (Don't) Know About the Beginning of the Universe

A plenary talk at the January 2017 meeting of the American Astronomical Society, on whether the universe truly had a beginning, and what might have come before.

Quantum entaglement

The document discusses the concept of quantum entanglement, which involves particles interacting in a way that measuring one particle instantly affects the other particle, even when separated by large distances. This was proposed in the EPR paradox by Einstein, Podolsky, and Rosen to argue against the completeness of quantum mechanics. The two options to resolve the EPR paradox are hidden variable theory or quantum entanglement. John Bell proved that no local hidden variable theory can match all predictions of quantum mechanics. Experiments by Aspect in 1981 supported quantum entanglement and ruled out hidden variables. While entanglement allows instantaneous correlations between particles, it does not allow for superluminal information transfer.

EPR paradox

The document provides an overview of the EPR paradox proposed by Einstein, Podolsky and Rosen in 1935. The key points are:
1) The EPR paradox uses a thought experiment involving two entangled particles to argue that quantum mechanics provides an incomplete description of physical reality.
2) By measuring properties of one particle, corresponding properties of the distant entangled particle can be known instantaneously, appearing to violate relativistic constraints on information transfer.
3) While Einstein believed there were "hidden variables" not accounted for in quantum mechanics, experiments have verified quantum mechanics and shown that measurements do not reveal pre-existing states.

Quantum Field Theory and the Limits of Knowledge

A seminar, given to philosophers, on how quantum field theory allows us to delineate known from unknown in fundamental physics, and why the laws of physics underlying everyday phenomena are known.

Quantum Entanglement - Cryptography and Communication

Quantum entanglement and quantum cryptography were discussed as potential technologies to improve communication security and reduce delays. Quantum key distribution uses quantum entanglement to securely generate and distribute encryption keys. However, the speed of light remains a fundamental limit on end-to-end communication delays. Faster-than-light transmission would be required to significantly shorten delays, which currently requires breakthroughs beyond existing physics theories.

Bethe salpeter equation

The document discusses the Bethe-Salpeter equation (BSE) which accounts for electron-hole interactions beyond the independent particle approximation. It summarizes that the BSE is derived from the equation of motion for the response function and results in an effective two-particle Hamiltonian that describes electron-hole excitations when diagonalized. Solving the BSE for lithium fluoride improves agreement with experimental optical spectra by including excitonic effects neglected by the independent particle picture.

Quantum teleportation

Power Point Presentation on Quantum Teleportation. 17 slides, easy elaboration and complete coverage on basic ideas of Teleportation Technology..

Density functional theory (DFT) and the concepts of the augmented-plane-wave ...

Density functional theory (DFT) is a quantum mechanical method used to investigate the electronic structure of materials. The document discusses DFT and the linearized augmented plane wave plus local orbital (LAPW+lo) method implemented in the Wien2k software. Wien2k is widely used to study the properties of solids and surfaces using an all-electron, relativistic, and full-potential DFT approach. The document provides an overview of the theoretical foundations of DFT and LAPW methods as well as examples of applications studied with Wien2k.

Quick and Dirty Introduction to Mott Insulators

Branislav K. Nikoli
ć
Department of Physics and Astronomy, University of Delaware, U.S.A.
PHYS 624: Introduction to Solid State Physics
http://www.physics.udel.edu/~bnikolic/teaching/phys624/phys624.html

Quantum Entanglement

Quantum entanglement allows two particles to be correlated in such a way that measuring one particle instantly affects the state of the other, even when separated by large distances. Einstein was skeptical of this "spooky action at a distance," but experiments have confirmed that quantum entanglement violates locality by demonstrating correlations between distant particles that match predictions. While information is not actually transmitted faster than light, the measurement of one particle's properties, such as spin, instantly determines the properties of the entangled particle regardless of distance.

Role of excitonic effects in nonlinear optical properties of 2D materials

The document discusses the role of excitonic effects in nonlinear optical properties of 2D materials. It presents a real-time approach to calculate nonlinear optics that includes excitonic effects using a dynamical polarization consistent with periodic boundary conditions. Calculations show excitonic effects enhance second harmonic generation at resonant energies in materials like MoS2 and h-BN. Excitonic effects also impact third harmonic generation by redistributing intensity and reducing it at resonant energies. The approach is implemented in an open source nonlinear optics module.

Lf 2020 langevin

A bunch of random ramblings on the Langevin equation, with some details on the Ito-Stratanovitch distinction

Quantum Entanglement

1. Quantum entanglement describes a phenomenon where two quantum particles interact in such a way that they become linked regardless of distance, so that measuring one particle instantly affects the state of the other.
2. Einstein was critical of quantum mechanics and its implications of "spooky action at a distance," which led to the development of experiments to test theories of quantum entanglement.
3. Repeated experiments confirmed the existence of quantum entanglement and disproved Einstein's theories, showing that entangled particles are truly linked regardless of distance.

Quantum entanglement

1) Quantum entanglement is a property where quantum states of objects cannot be described independently, even if separated spatially. A practical example involves two cups of hot chocolate where tasting one instantly reveals the other's state.
2) Bra-ket notation is used to describe quantum states as vectors or functionals in a Hilbert space. Operators act on these states to model physical quantities.
3) A qubit is the quantum analogue of a classical bit, existing in superposition of states |0> and |1>. Quantum computers use entanglement between qubits to perform computations in parallel.

Quantum tunneling composite

This document discusses quantum tunneling and quantum tunneling composite materials. It begins with an overview of quantum tunneling and how it allows particles to pass through barriers they classically could not. It then describes quantum tunneling composite materials, which use the quantum tunneling effect to create sensors. When flexed, the materials change from insulators to conductors, allowing them to detect forces. The document discusses several potential applications of these new quantum tunneling composite sensors in areas like toys, sports, medicine, tools, robotics and keyboards.

Schrodinger cat (Copenhagen & Many-worlds interpretation + phase-damping)

1) The Schrodinger's cat thought experiment proposes that a cat trapped in a sealed box with a radioactive atom could be considered both alive and dead before being observed.
2) According to the Copenhagen interpretation, the cat exists in a superposition of states before observation, at which point the wave function collapses and the cat is observed to be definitively alive or dead.
3) The many-worlds interpretation suggests that observation causes the universe to split into multiple worlds where the cat is observed to be alive in one world and dead in another.

Nanomagnetism columbia 2013

Quantum Nanomagnetism and related phenomena
Professor Javier Tejada presented on topics related to quantum nanomagnetism including: (1) exchange and anisotropy energies that determine magnetic behavior on small scales; (2) single domain particles whose magnetic moments behave collectively; (3) molecular magnets that exhibit quantum tunneling of magnetization and resonant spin tunneling; and (4) phenomena such as quantum magnetic deflagration and potential evidence of superradiance observed in molecular magnet experiments using pulsed magnetic fields. Future directions may explore stabilizing molecular magnets above liquid nitrogen temperatures and their potential applications in memory and quantum computing.

"Squeezed States in Bose-Einstein Condensate"

1. The document discusses the formation of squeezed quantum states in Bose-Einstein condensates trapped in optical lattices. By slowly ramping up the depth of the optical lattice, the atoms can be prepared in a number-squeezed state.
2. Releasing the atoms from the lattice allows their wavefunctions to overlap and interfere, providing a way to probe the quantum phase state of the atoms. Number-squeezed states are observed to produce interference patterns with higher contrast than coherent states.
3. Variational calculations of the quantum state dynamics during lattice ramping and dephasing agree qualitatively with experimental observations of the transition between coherent and squeezed states.

Cosmology

This document discusses the relationship between amplitudes and cosmology. Amplitude methods have led to advances in computing cosmological correlations through recursion relations and generalized unitarity. Observations of the CMB and large-scale structure have revealed properties of the primordial fluctuations, including near scale-invariance, adiabaticity, and Gaussianity. Models of inflation aim to explain these properties, and the effective field theory of inflation provides a framework to study fluctuations beyond slow-roll. Future experiments will further probe the initial conditions and search for signatures of the ultraviolet completion of inflation such as non-Gaussianity and tensor modes.

On the Origin of Structure in the Universe

1) The talk discusses the origin of structure in the universe, from the small density fluctuations after the Big Bang to the galaxies, stars and planets we see today.
2) It explains how quantum fluctuations during an early period of exponential expansion called inflation were stretched to cosmological scales by inflation, seeding these initial density fluctuations.
3) The talk outlines how measurements of the cosmic microwave background have revealed correlations in the fluctuations that can only be explained by a period of inflation in the early universe that was faster than the speed of light.

Letting Go of Spacetime

A short talk on why quantum gravity should make us suspicious of locality as a fundamental principle of physics.

Many Worlds, the Born Rule, and Self-Locating Uncertainty

A semi-technical talk on deriving the Born Rule for quantum probabilities in the Everett (many-worlds) formulation of quantum mechanics.

What We (Don't) Know About the Beginning of the Universe

A plenary talk at the January 2017 meeting of the American Astronomical Society, on whether the universe truly had a beginning, and what might have come before.

Quantum entaglement

The document discusses the concept of quantum entanglement, which involves particles interacting in a way that measuring one particle instantly affects the other particle, even when separated by large distances. This was proposed in the EPR paradox by Einstein, Podolsky, and Rosen to argue against the completeness of quantum mechanics. The two options to resolve the EPR paradox are hidden variable theory or quantum entanglement. John Bell proved that no local hidden variable theory can match all predictions of quantum mechanics. Experiments by Aspect in 1981 supported quantum entanglement and ruled out hidden variables. While entanglement allows instantaneous correlations between particles, it does not allow for superluminal information transfer.

EPR paradox

The document provides an overview of the EPR paradox proposed by Einstein, Podolsky and Rosen in 1935. The key points are:
1) The EPR paradox uses a thought experiment involving two entangled particles to argue that quantum mechanics provides an incomplete description of physical reality.
2) By measuring properties of one particle, corresponding properties of the distant entangled particle can be known instantaneously, appearing to violate relativistic constraints on information transfer.
3) While Einstein believed there were "hidden variables" not accounted for in quantum mechanics, experiments have verified quantum mechanics and shown that measurements do not reveal pre-existing states.

Quantum Field Theory and the Limits of Knowledge

A seminar, given to philosophers, on how quantum field theory allows us to delineate known from unknown in fundamental physics, and why the laws of physics underlying everyday phenomena are known.

Quantum Entanglement - Cryptography and Communication

Quantum entanglement and quantum cryptography were discussed as potential technologies to improve communication security and reduce delays. Quantum key distribution uses quantum entanglement to securely generate and distribute encryption keys. However, the speed of light remains a fundamental limit on end-to-end communication delays. Faster-than-light transmission would be required to significantly shorten delays, which currently requires breakthroughs beyond existing physics theories.

Bethe salpeter equation

The document discusses the Bethe-Salpeter equation (BSE) which accounts for electron-hole interactions beyond the independent particle approximation. It summarizes that the BSE is derived from the equation of motion for the response function and results in an effective two-particle Hamiltonian that describes electron-hole excitations when diagonalized. Solving the BSE for lithium fluoride improves agreement with experimental optical spectra by including excitonic effects neglected by the independent particle picture.

Quantum teleportation

Power Point Presentation on Quantum Teleportation. 17 slides, easy elaboration and complete coverage on basic ideas of Teleportation Technology..

Density functional theory (DFT) and the concepts of the augmented-plane-wave ...

Density functional theory (DFT) is a quantum mechanical method used to investigate the electronic structure of materials. The document discusses DFT and the linearized augmented plane wave plus local orbital (LAPW+lo) method implemented in the Wien2k software. Wien2k is widely used to study the properties of solids and surfaces using an all-electron, relativistic, and full-potential DFT approach. The document provides an overview of the theoretical foundations of DFT and LAPW methods as well as examples of applications studied with Wien2k.

Quick and Dirty Introduction to Mott Insulators

Branislav K. Nikoli
ć
Department of Physics and Astronomy, University of Delaware, U.S.A.
PHYS 624: Introduction to Solid State Physics
http://www.physics.udel.edu/~bnikolic/teaching/phys624/phys624.html

Quantum Entanglement

Quantum entanglement allows two particles to be correlated in such a way that measuring one particle instantly affects the state of the other, even when separated by large distances. Einstein was skeptical of this "spooky action at a distance," but experiments have confirmed that quantum entanglement violates locality by demonstrating correlations between distant particles that match predictions. While information is not actually transmitted faster than light, the measurement of one particle's properties, such as spin, instantly determines the properties of the entangled particle regardless of distance.

Role of excitonic effects in nonlinear optical properties of 2D materials

The document discusses the role of excitonic effects in nonlinear optical properties of 2D materials. It presents a real-time approach to calculate nonlinear optics that includes excitonic effects using a dynamical polarization consistent with periodic boundary conditions. Calculations show excitonic effects enhance second harmonic generation at resonant energies in materials like MoS2 and h-BN. Excitonic effects also impact third harmonic generation by redistributing intensity and reducing it at resonant energies. The approach is implemented in an open source nonlinear optics module.

Lf 2020 langevin

A bunch of random ramblings on the Langevin equation, with some details on the Ito-Stratanovitch distinction

Quantum Entanglement

1. Quantum entanglement describes a phenomenon where two quantum particles interact in such a way that they become linked regardless of distance, so that measuring one particle instantly affects the state of the other.
2. Einstein was critical of quantum mechanics and its implications of "spooky action at a distance," which led to the development of experiments to test theories of quantum entanglement.
3. Repeated experiments confirmed the existence of quantum entanglement and disproved Einstein's theories, showing that entangled particles are truly linked regardless of distance.

Quantum entanglement

1) Quantum entanglement is a property where quantum states of objects cannot be described independently, even if separated spatially. A practical example involves two cups of hot chocolate where tasting one instantly reveals the other's state.
2) Bra-ket notation is used to describe quantum states as vectors or functionals in a Hilbert space. Operators act on these states to model physical quantities.
3) A qubit is the quantum analogue of a classical bit, existing in superposition of states |0> and |1>. Quantum computers use entanglement between qubits to perform computations in parallel.

Quantum tunneling composite

This document discusses quantum tunneling and quantum tunneling composite materials. It begins with an overview of quantum tunneling and how it allows particles to pass through barriers they classically could not. It then describes quantum tunneling composite materials, which use the quantum tunneling effect to create sensors. When flexed, the materials change from insulators to conductors, allowing them to detect forces. The document discusses several potential applications of these new quantum tunneling composite sensors in areas like toys, sports, medicine, tools, robotics and keyboards.

Schrodinger cat (Copenhagen & Many-worlds interpretation + phase-damping)

1) The Schrodinger's cat thought experiment proposes that a cat trapped in a sealed box with a radioactive atom could be considered both alive and dead before being observed.
2) According to the Copenhagen interpretation, the cat exists in a superposition of states before observation, at which point the wave function collapses and the cat is observed to be definitively alive or dead.
3) The many-worlds interpretation suggests that observation causes the universe to split into multiple worlds where the cat is observed to be alive in one world and dead in another.

Cosmology

Cosmology

On the Origin of Structure in the Universe

On the Origin of Structure in the Universe

Letting Go of Spacetime

Letting Go of Spacetime

Many Worlds, the Born Rule, and Self-Locating Uncertainty

Many Worlds, the Born Rule, and Self-Locating Uncertainty

What We (Don't) Know About the Beginning of the Universe

What We (Don't) Know About the Beginning of the Universe

Quantum entaglement

Quantum entaglement

EPR paradox

EPR paradox

Quantum Field Theory and the Limits of Knowledge

Quantum Field Theory and the Limits of Knowledge

Quantum Entanglement - Cryptography and Communication

Quantum Entanglement - Cryptography and Communication

Bethe salpeter equation

Bethe salpeter equation

Quantum teleportation

Quantum teleportation

Density functional theory (DFT) and the concepts of the augmented-plane-wave ...

Density functional theory (DFT) and the concepts of the augmented-plane-wave ...

Quick and Dirty Introduction to Mott Insulators

Quick and Dirty Introduction to Mott Insulators

Quantum Entanglement

Quantum Entanglement

Role of excitonic effects in nonlinear optical properties of 2D materials

Role of excitonic effects in nonlinear optical properties of 2D materials

Lf 2020 langevin

Lf 2020 langevin

Quantum Entanglement

Quantum Entanglement

Quantum entanglement

Quantum entanglement

Quantum tunneling composite

Quantum tunneling composite

Schrodinger cat (Copenhagen & Many-worlds interpretation + phase-damping)

Schrodinger cat (Copenhagen & Many-worlds interpretation + phase-damping)

Nanomagnetism columbia 2013

Quantum Nanomagnetism and related phenomena
Professor Javier Tejada presented on topics related to quantum nanomagnetism including: (1) exchange and anisotropy energies that determine magnetic behavior on small scales; (2) single domain particles whose magnetic moments behave collectively; (3) molecular magnets that exhibit quantum tunneling of magnetization and resonant spin tunneling; and (4) phenomena such as quantum magnetic deflagration and potential evidence of superradiance observed in molecular magnet experiments using pulsed magnetic fields. Future directions may explore stabilizing molecular magnets above liquid nitrogen temperatures and their potential applications in memory and quantum computing.

"Squeezed States in Bose-Einstein Condensate"

1. The document discusses the formation of squeezed quantum states in Bose-Einstein condensates trapped in optical lattices. By slowly ramping up the depth of the optical lattice, the atoms can be prepared in a number-squeezed state.
2. Releasing the atoms from the lattice allows their wavefunctions to overlap and interfere, providing a way to probe the quantum phase state of the atoms. Number-squeezed states are observed to produce interference patterns with higher contrast than coherent states.
3. Variational calculations of the quantum state dynamics during lattice ramping and dephasing agree qualitatively with experimental observations of the transition between coherent and squeezed states.

Introduction to the phenomenology of HiTc superconductors.

1. The document provides an introduction to the phenomenology of high-temperature superconductors (HiTc).
2. It discusses the basic physics of doped Mott insulators and experimental methods used to study HiTc superconductors such as thermodynamic measurements, transport properties, neutron scattering, and ARPES.
3. It also covers topics such as the pseudo-gap phase, the one-hole problem, properties at small doping levels, and properties of the superconducting state.

Theoretical picture: magnetic impurities, Zener model, mean-field theory

The document summarizes the theoretical picture of dilute magnetic semiconductors (DMS). It describes the Zener model where magnetic impurities interact with charge carriers via exchange interaction. It then discusses the mean field approximation used to calculate the Curie temperature. For higher doping concentrations, a virtual crystal approximation is used to replace impurity spins with a smooth spin density. The model explains several experimental observations but cannot explain some properties like the shape of magnetization curves. At very low doping, a bound magnetic polaron model applies where carriers hop between localized acceptor levels aligned with impurity spins.

Sergey Sibiryakov "Galactic rotation curves vs. ultra-light dark matter: Impl...

The document discusses ultra-light dark matter and its implications for galactic rotation curves. It begins by providing theoretical background on ultra-light dark matter and how it can form soliton cores within dark matter halos. It then discusses how the properties of these soliton cores, such as their mass and size, relate to the properties of the ultra-light dark matter particle. Finally, it discusses how measurements of galactic rotation curves could provide insights into ultra-light dark matter models by probing the presence and characteristics of these soliton cores.

Lecture15_Hall_effect.pdf

The Hall effect occurs when a current-carrying conductor is placed in a magnetic field. This causes charge carriers to experience a Lorentz force and build up on one side of the conductor, creating a voltage (the Hall voltage) perpendicular to both the current and the magnetic field. Measuring the Hall voltage allows determining properties of the charge carriers such as their type (electrons or holes) and density. The classical Drude model describes the Hall effect by considering electrons as particles scattering between collisions. It relates the Hall coefficient to the carrier density, providing a way to experimentally measure carrier density via the Hall effect.

Topological flat bands without magic angles in massive twisted bilayer graphe...

Topological flat bands without magic angles in massive twisted bilayer graphenes (Srivani. et.al., Phys. Rev. B 101, 125411(2020))

Quantum Nanomagetism (USA, 2011)

This document summarizes research conducted at Universitat de Barcelona from 1990-2010 on quantum magnetism. It discusses several key topics: (1) quantum relaxation from 1990-1996, where relaxation rates were studied in thin films; (2) resonant spin tunneling from 1996-2010, where an external magnetic field causes energy level crossings allowing spin tunneling; (3) quantum magnetic deflagration, where a "flame front" of spin reversal propagates through a crystal; and (4) superradiance, where coherent emission of photons occurs as spins decay to the ground state. The rotational Doppler effect is also discussed as it applies to magnetic resonance techniques.

Lecture 7 pseudogap

This document summarizes key aspects of the pseudogap phase in cuprate superconductors. It begins with an overview of the hole-doped phase diagram and experimental probes such as ARPES. It then discusses several notable features of the pseudogap phase revealed by these experiments, including the existence of a gap above the superconducting dome and Fermi arcs that shrink with temperature. Several competing orders that may be related to the pseudogap are also noted. The document concludes with a discussion of BCS-BEC crossover theories as a possible explanation for pseudogap physics in the cuprates based on similarities to phenomena in cold atom systems.

Crystal structure analysis

This document discusses various techniques for crystal structure analysis using diffraction methods, including X-ray diffraction, electron diffraction, and neutron diffraction. It provides background on the essential physics of Bragg diffraction and scattering. Key topics covered include generating X-rays, basic diffractometer setups, powder and thin film diffraction techniques, and applications such as phase identification and structure determination.

Manhpowerpoint

The document summarizes research on the magnetic properties and magnetocaloric effect of two materials: La2NiMnO6 nanocrystals and a single crystal of La1.2Sr1.8Mn2O7. For both materials, the document examines structural properties, magnetic phase transitions, critical behavior near the Curie temperature, and magnetocaloric effects. Key results include determining the materials undergo second-order phase transitions and exhibit short-range ferromagnetic order. The magnetocaloric effect is also investigated through measurements of magnetic entropy change and development of universal curves for both materials.

Mcrowave and Radar engineering

R,L,C, G parameters of a co-axial & 2-wire transmission line
Field solutions for TE and TM modes for a waveguide
Design and analysis of rectangular waveguide to support TE10 mode
Design and analysis of circular waveguide to support TE11 mode

Workshop problems solving

Prof. Dr. Ahmed Ennaoui
Photovoltaic Solar Energy Conversion
Advanced exercices
ENIM Rabat Morocco
إنتاج الكهرباء من الطاقة الشمسية

.wave deformation

This document summarizes key concepts about wave deformation, including refraction, diffraction, and breaking. It discusses how wave refraction causes wave crests to bend toward depth contours as waves propagate into shallower water. Diffraction causes wave energy to spread laterally around barriers. Wave breaking occurs when the wave steepness exceeds certain thresholds and depends on beach slope. It classifies breakers as spilling, plunging, or surging based on wave and slope characteristics. Refraction diagrams and formulas are presented to analyze wave behavior near coastal structures.

Flow Induced vibration fundamentals present

Flow induced vibration

4 radio wave propagation over the earth

Describes the Electromagnetic Wave Propagation over the Earth Surface. Please send comments to solo.hermelin@gmail.com.
For more presentations on different subjects pleade visit my website at http://www,solohermelin.com.
This presentation is in the Radar folder.

Chapter 4a interference

When two light waves pass through the same point in space simultaneously, interference occurs. Constructive interference happens when the waves are in phase and add to produce a larger wave, while destructive interference occurs when they are out of phase and cancel each other out. The intensity of the resulting interference pattern depends on the phase difference between the waves. In a double slit experiment, the phase difference and resulting interference is determined by the path length difference between waves passing through each slit.

Quantum information probes

1) The document discusses using quantum probes to indirectly extract information about complex quantum systems like ultracold atomic gases, without directly measuring the system.
2) One method is to use an impurity atom as a qubit probe immersed in a 2D Bose-Einstein condensate. Interactions between the probe and gas induce decoherence on the probe that depends on properties of the gas like dimensionality and phase fluctuations, allowing characterization of the gas.
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- 1. Gravitational Collider Physics Daniel Baumann
- 2. Based on work with H.S. Chia R. Porto J. Stout G. Tomaselli G. Bertone DB, Chia and Porto Probing Ultralight Bosons with Binary Black Holes arXiv:1804.03208 PRD [Editor’s Suggestion] DB, Chia, Porto and Stout Gravitational Collider Physics arXiv:1912.04932 DB, Bertone, Stout and Tomaselli Ionization of Gravitational Atoms arXiv:2112.14777 DB, Bertone, Stout and Tomaselli Sharp Signals of Boson Clouds in Black Hole Binary Inspirals arXiv:22xx.xxxxx (PRL accepted) [Editor’s Suggestion] DB, Chia, Stout and ter Haar The Spectra of Gravitational Atoms arXiv:1908.10370
- 3. Can it also become a new tool for fundamental physics? The detection of GWs marked the beginning of a new era of multi-messenger astronomy:
- 4. particle collider Standard Model Neutrinos 1020 1010 1 10 10 10 20 Energy [eV] New physics is often associated with high energies (short distances): We expect this to have small effects on long-wavelength GW signals. cosmological collider
- 5. New physics may also occur at low energies, if it is weakly coupled: particle collider Standard Model Neutrinos 1020 1010 1 10 10 10 20 Energy [eV] EM Strong Weak Gravity Coupling gravitational collider This may be probed by GW signals from binary black hole mergers. cosmological collider
- 6. superradiance Ultralight bosons can form bound states around rotating black holes: This resembles the hydrogen atom and is therefore often called a gravitational atom. Zel’dovich ’72 Starobinsky ’73 Arvanitaki et al ‘09 superradiance
- 7. A companion will perturb the cloud with a slowly increasing frequency. DB, Chia, Porto, and Stout ’19
- 8. DB, Chia, Porto, and Stout ’19 This interaction is enhanced at certain resonance frequencies.
- 9. DB, Chia, Porto, and Stout ’19 The backreaction of the cloud’s dynamics on the orbit leaves distinct imprints in the gravitational waves emitted by the binary.
- 10. Outline 1) Gravitational Atoms 2) Evolution in Binaries 3) Gravitational Wave Signals
- 12. A scalar field around a rotating black hole is described by the KG equation: g↵ r↵r µ2 = 0 We will focus on fields whose Compton wavelength is larger than the BH: Ultralight Bosons around Black Holes 1 km 1010 km 10 10 eV 10 20 eV
- 13. Such light fields see the far-field limit of the geometry: Ultralight Bosons around Black Holes µ2 ds2 = ✓ 1 2↵ r ◆ dt2 + ✓ 1 + 2↵ r ◆ dr2 4↵2 ã sin2 ✓ r dt d + r2 d⌦2 where ↵ ⌘ rg/ c is the gravitational fine-structure constant. spin i d dt = ✓ 1 2µ r2 ↵ r + V ◆ The KG equation then reduces to a Schrödinger equation: with = (t, x)eiµt Coulomb potential fine structure corrections V
- 14. 0 2 6 12 αr |ψ n!m (r)| 2 |10m! |21m! |32m! |43m! Bound States The energy eigenstates are the same as those of the hydrogen atom: with “quantum numbers”: principal orbital azimuthal m ` n r/r0
- 15. 0 5 10 µαr |ψ k;!m (r)| 2 |0; 11! |1; 11! |2; 11! |3; 11! |211! Unbound States There are also unbound continuum states: r/r0 with “quantum numbers”: energy orbital azimuthal m ` E
- 16. Bound State Spectrum En`m = µ ✓ 1 ↵2 2n2 + fn`↵4 + hn`m↵5 + · · · ◆ The bound state spectrum is the same as for the hydrogen atom: ! = 0 |211! |311! ! = 1 |322! ! = 2 n = 1 n = 2 n = 3
- 17. ` = 0 |211i |311i ` = 1 |322i ` = 2 n = 1 n = 2 n = 3 Growing and Decaying Modes Unlike in the hydrogen atom, the states are only quasi-stationary: !n`m = En`m + i n`m decaying growing
- 18. ΩH ω < mΩH Superradiant Scattering The growing modes are populated by superradiance: Outgoing wave Incoming wave / exp(im i!t) This is the wave analog of the Penrose process. Penrose ’71 Zel’dovich ’72 Starobinsky ’73
- 19. Black Hole Bomb A reflecting mirror around the BH creates a black hole bomb: Press and Teukolsky ‘72
- 20. For a massive field, the mirror is provided by the angular momentum barrier: This creates an exponential amplification of small fluctuations. Superradiant Instability
- 21. Growth Rates 1013 1011 109 107 105 103 10 0.02 0.05 0.1 0.15 0.2 0.25 α |211! |322! |321! The different bound states grow at different rates: n`m / ↵4`+5 Detweiler ‘80
- 22. Initial State of the Cloud adiance The fastest growing mode is the state We take this as the initial state of the cloud. 1 211 = 103 yrs ✓ M 60M ◆ ✓ 0.04 ↵ ◆9 |211i:
- 23. T211 = 1010 yrs ✓ M 60M ◆ ✓ 0.04 ↵ ◆15 Lifetime of the Cloud adiance In isolation, the gravitational atom is very long lived: We would like to understand what happens to the atom when it is part of a binary system.
- 25. The binary companion can induce transitions between bound states (“Rabi oscillations”) and excite unbound states (“photoelectric effect”): DB, Chia and Porto 2018 DB, Chia, Porto and Stout 2019 DB, Bertone, Stout and Tomaselli 2021
- 26. We will first study the transitions between bound states: Ω = ∆E ∆E DB, Chia and Porto 2018 DB, Chia, Porto and Stout 2019
- 27. Gravitational Perturbation ϕ∗ M∗ R∗ In a binary, the cloud gets perturbed at a slowly increasing frequency: i d dt = ✓ 1 2µ r2 ↵ r + V + V⇤(R⇤(t), '⇤(t)) ◆ This perturbation induces level mixing: ha|V⇤(t)|bi = ⌘ab(t)e i(ma mb)'⇤(t)
- 28. ⌦i = Ei mi ⇠ 0.01 Hz ✓ 60M M ◆ ⇣ ↵ 0.04 ⌘3 Resonant Transitions At specific frequencies, the perturbation is resonantly enhanced: ⌦1 ⌦2 ⌦3
- 29. Selection Rules ! = 0 |211! ∆E |311! |31 −1! ! = 1 |322! ! = 2 n = 1 n = 2 n = 3 For a scalar atom, the level mixings typically involve only two states. Only certain transitions are allowed by selection rules:
- 30. Ω = ∆E ϕ∗(t) ηeiϕ∗(t) ηe−iϕ∗(t) ∆E Two-State System A simple two-state system is therefore a good model for the dynamics: H = 1 2 E ⌘ei'⇤(t) ⌘e i'⇤(t) 1 2 E !
- 31. HD = (⌦(t) E)/2 ⌘ ⌘ (⌦(t) E)/2 ! Two-State System Rotating along with the companion, isolates the slow motion: E
- 32. Near the resonance, we can write ⌦(t) = ⌦res + t determines nature of transition HD(t) = t 2 ✓ 1 0 0 1 ◆ + ⌘ ✓ 0 1 1 0 ◆ Landau ’32 Zener ’32 E Two-State System
- 33. Landau-Zener Transition Landau ’32 Zener ’32 The analogous problem in QM was solved by Landau and Zener. The evolution depends on the size of the parameter : z ⌘ ⌘2 / 40 20 0 20 40 0 0.5 1 z = 102 p t |c a (t)| 2 40 20 0 20 40 0 0.5 1 z = 10 2 p t |c0|2 |c1|2 • For slow transitions, the initial state gets fully converted. • For fast transitions, some of the initial state can survive.
- 34. Multi-State Transitions Clouds of spinning particles involve multi-state transitions: 50 0 50 100 150 0 0.5 1 p t |c a (t)| 2 |c1|2 |c2|2 |c3|2 50 0 50 p t • The final state is generically a superposition of states. • There can be neutrino-like oscillations between the states.
- 35. Backreaction on the Orbit The transitions force the cloud’s energy and angular momentum to change: tbefore tres tafter Sc(t) Sc(t) tres These changes must be balanced by changes in the orbital dynamics.
- 36. Backreaction on the Orbit Conservation of angular momentum requires d dt ⇣ L + Sc ⌘ = TGW ⇡ 0 cloud orbit The dynamics of the cloud affects the orbital motion! DB, Chia, Porto, and Stout ’20
- 37. 1 0.5 0 0.5 1 1.5 2 0 0.5 1 1.5 2 t/⌦r ⌦/⌦ r 1 0.5 0 0.5 1 t/⌦r Floating Orbits The binary floats when it absorbs angular momentum from the cloud: The binary emits transient, nearly monochromatic GWs. DB, Chia, Porto, and Stout ’20
- 38. 1 0.5 0 0.5 1 1.5 2 0 0.5 1 1.5 2 t/⌦r ⌦/⌦ r 1 0.5 0 0.5 1 t/⌦r Sinking Orbits The binary sinks when it releases angular momentum to the cloud: This leads to a dephasing in the GW signal. DB, Chia, Porto, and Stout ’20
- 39. Multiple Transitions The sequence of transitions is a fingerprint of the atomic spectra: ⌦1 ⌦2 ⌦3 t ⌦(t) ⌦1 ⌦2 ⌦3
- 40. Multiple Transitions The evolution can be described by a series of scattering events: ⌦1 ⌦2 ⌦3 ⌦(t) = ⌦1 ⌦(t) = ⌦2 ⌦(t) = ⌦3 t | i S1| i S2S1| i S3S2S1| i DB, Chia, Porto, and Stout ’20
- 41. Final State of the Cloud Qc(t) = X a |ca(t)|2 Qc,a + X a6=b |ca(t)cb(t)| Qab cos( Eab t) scalar cloud vector cloud The S-matrix formalism predicts the final state of the cloud: |f i = N Y n=1 Sn | i i The shape and time dependence of this state depends on the internal structure of the cloud:
- 42. E Gravitational Collider Physics • Mass: Position of the resonance • Spin: Angular dependence • Mass: Position of the resonances • Spin: Structure of the final state As in ordinary particle colliders, the signals depend on the mass and spin of the particles:
- 43. 10 -3 10 -2 10 -1 1 2 fres (Hz) 10 -1 1 10 102 103 104 M § /M 1 0 - 6 1 0 - 4 1 0 - 2 1 1 0 2 1% 10% 100% M = 60MØ 0.01 0.05 0.1 0.2 0.3 Æ 10 -8 10 -6 10 -4 10 -2 1 102 104 ¢t tot (yrs) Gravitational Wave Signatures • The resonances naturally occur in the LISA band: • The dephasing of the signals can be significant:
- 45. What happens when the orbital frequency becomes large enough to excite transitions to unbound states? Ω = Eb E Eb DB, Bertone, Stout and Tomaselli 2021
- 46. Fermi’s Golden Rule The transition rate (per unit energy) is given by Fermi’s Golden Rule: Ω = Eb ϕ∗(t) −Eb E η!m(E)eiϕ∗(t) η!m(E)e−iϕ∗(t) Eb d `m = dE ⌘`m(E; t) 2 E Eb ⌥ (m mb)⌦(t) level mixing: hE; `m|V⇤(t)|nb`bmbi 2
- 47. Pion(t) = Mc(t) µ X `,m (m mb) ⌦(t) ⌘`m E (m) ⇤ ; t 2 ⇥ E (m) ⇤ Ionization Power Ω = Eb ϕ∗(t) −Eb E η!m(E)eiϕ∗(t) η!m(E)e−iϕ∗(t) Eb Summing over all bound states gives the total ionization power: E (m) ⇤ ⌘ Eb ± (m mb) ⌦(t)
- 48. Ionization Power • The orbital energy lost due to ionization can be very large. | (R )|2 300 200 100 0 0 100 200 R /M P ion /P GW Evaluating this numerically, we find • It has sharp features are specific separations: R (g) ⇤ = M ↵2 4g2 ✓ 1 + M⇤ M ◆ n4 b 1/3 , g = 1, 2, · · ·
- 49. 0 200 400 600 800 10 200 400 + t [yrs] R ∗ /M Backreaction on the Orbit Ionization can significantly shorten the merger time:
- 50. Frequency Evolution We get sharp features in the frequency evolution of the GW signals: −20 −15 −10 −5 0 t − tmerg (f / ) −8/3 f(2) f(3) f(4) These discontinuities are distinctive signatures of the boson clouds.
- 52. • Precise waveform modeling is needed to apply this to GW searches. • We studied the dynamics of boson clouds in black hole binaries. • The backreaction on the orbit produces distinct GW signatures.
- 53. Thank you for your attention!