Conference

Displaying 2797 - 2808 of 5122

Optical magnetometry - From basics to Global Network of Optical Magnetometer for Exotic physics
- Nathan Leefer University of California, Berkeley
- Szymon Pustelny University of California, Berkeley
June 19, 2014

PIRSA:14060032
Free Discussion

June 18, 2014

PIRSA:14060031
Search for new physics in atoms: cosmic PNC and variation of alpha

Vladimir Dzuba University of New South Wales (UNSW)

June 18, 2014

PIRSA:14060030
Ultra-light hidden photons

Jeremy Mardon California Institute of Technology

June 18, 2014

PIRSA:14060029
Axion-induced effects and topological defect dark matter detection schemes

Yevgeny Stadnik University of New South Wales (UNSW)

June 18, 2014

PIRSA:14060028
Astrophysical and cosmological aspects of feebly-interacting light species

Josef Pradler Austrian Academy of Sciences

June 18, 2014

PIRSA:14060027
Cosmological Constraints on Ultra-light Axions

David Marsh King's College London

June 18, 2014

PIRSA:14060026
Axions: Past, Present and Future

Surjeet Rajendran Stanford University

June 18, 2014

PIRSA:14060025
Inflationary Gravitational Waves: Recent Developments and Next Steps

Marc Kamionkowski Johns Hopkins University - Department of Physics & Astronomy

June 18, 2014

PIRSA:14060024
Precision Spectroscopy of Atomic Lithium

Jason Stalnaker Oberlin College

June 17, 2014

PIRSA:14060022
A quantum network of clocks

Mikhail Lukin Harvard University

June 17, 2014

PIRSA:14060021
Dark Energy and Testing Gravity

Raman Sundrum University of Maryland, College Park

June 17, 2014

PIRSA:14060020

Optical magnetometry - From basics to Global Network of Optical Magnetometer for Exotic physics
- Nathan Leefer University of California, Berkeley
- Szymon Pustelny University of California, Berkeley
June 19, 2014

PIRSA:14060032

In our talk we seek to present a broad overview of the field of optical magnetometers, starting from basic principles to fundamental limitations to the variety of applications in which they have already found use. We will end with a report on the development of a new worldwide network of synchronized magnetometers that can be used to search for a variety of new physical phenomena (many of which are discussed at this conference!).
Free Discussion

June 18, 2014

PIRSA:14060031
Search for new physics in atoms: cosmic PNC and variation of alpha

Vladimir Dzuba University of New South Wales (UNSW)

June 18, 2014

PIRSA:14060030

We consider pseudo-scalar and pseudo-vector interaction of atomic electrons with hypothetical dark matter particles (e.g., axions). These interactions lead to oscillating atomic parity non-conserving (PNC) amplitudes and/or oscillating electric dipole moments (EDM). In static
limit for PNC, existing atomic PNC experiments can be used to constrain time component of the pseudo-vector field.

Possible variation of fundamental constants is suggested by theories unifying gravity with other interactions. Evidence of the space/time variation of the fine structure constant alpha is found in
the quasar absorption spectra. Optical transitions in highly charged ions can be used as sensitive tools for studying time variation of alpha in laboratory.
Ultra-light hidden photons

Jeremy Mardon California Institute of Technology

June 18, 2014

PIRSA:14060029
Axion-induced effects and topological defect dark matter detection schemes

Yevgeny Stadnik University of New South Wales (UNSW)

June 18, 2014

PIRSA:14060028

We discuss new observable effects of axionic dark matter in atoms, molecules and nuclei. We show that the interaction of an axion field, or in general a pseudoscalar field, with the axial-vector current generated by an electron through a derivative-type coupling can give rise to a time-dependent mixing of opposite-parity states in atomic and molecular systems. Likewise, the analogous interaction of an axion field with the axial-vector current generated by a nucleon can give rise to time-dependent mixing of opposite-parity states in nuclear systems. This mixing can induce oscillating electric dipole moments, oscillating parity nonconservation effects and oscillating anapole moments in such systems. By adjusting the energy separation between the opposite-parity states of interest to match the axion mass energy, axion-induced experimental observables can be enhanced by many orders of magnitude. Oscillating atomic electric dipole moments can also be generated by axions through hadronic mechanisms, namely the P,T-violating nucleon-nucleon interaction and through the axion-induced electric dipole moments of valence nucleons, which comprise the nuclei. The axion field is modified by Earth’s gravitational field. The interaction of the spin of either an electron or nucleon with this modified axion field leads to axion-induced observable effects. These effects, which are of the form g • σ, differ from the axion-wind effect, which has the form pa • σ.

We also propose schemes for the detection of topological defect dark matter using pulsars and other luminous extraterrestrial systems via non-gravitational signatures. The dark matter field, which makes up a defect, may interact with standard model particles, including quarks and the photon, resulting in the alteration of their masses. When a topological defect passes through a pulsar, its mass, radius and internal structure may be altered, resulting in a pulsar `quake'. A topological defect may also function as a cosmic dielectric material with a frequency-dependent index of refraction, which would give rise to the time delay of a periodic extraterrestrial light or radio signal, and the dispersion of a light or radio source in a similar manner to an optical lens. The biggest advantage of such astrophysical observations over recently proposed terrestrial detection methods is the much higher probability of a defect been found in the vast volumes of outer space compared with one passing through Earth itself.

References: (1) Phys. Rev. D 89, 043522 (2014).
(2) arXiv:1404.2723.
(3) arXiv:1405.5337.
Astrophysical and cosmological aspects of feebly-interacting light species

Josef Pradler Austrian Academy of Sciences

June 18, 2014

PIRSA:14060027

More often than not, astrophysical probes are superior to direct laboratory tests when considering light, very weekly interacting particles and it takes clever strategies and/or ultra-pure experimental setups for direct tests to be competitive. In this talk, I will review the astrophysical side of the story with a particular focus on dark photons and axion-like particles. I will also present some recent results on the emission process of dark photons with mass below 10 keV from the interior of stars. Compared to previous analyses, limits on dark photons are significantly improved, to the extent that many dedicated experimental searches find themselves inside astrophysically excluded regions. However, constraints on the atomic ionization rate from a solar flux imposed by Dark Matter experiments offer a new test of such states, surpassing even the most stringent astrophysical limits. The model also serves as a prototype scenario for energy injection in the early Universe and I will show how cosmology offers unique sensitivity when laboratory probes are out of reach. Time permitting, I may also briefly comment on very light axions and their cosmology.
Cosmological Constraints on Ultra-light Axions

David Marsh King's College London

June 18, 2014

PIRSA:14060026

Ultra-light axions (ULAs) with masses in the range 1e-33 eV< m < 1e-18 eV can constitute a novel component of the dark matter, which can be constrained by cosmological observations. ULA dark matter (DM) is produced non-thermally via vacuum realignment in the early universe and is cold. Pressure perturbations, however, manifest a scale in the clustering (also the de Broglie scale). For the range of masses considered this spans the Hubble scale down to sub-galactic scales. In the model-independent adiabatic mode of initial conditions, one can gain strong constraints on ULAs as DM from the CMB and large scale structure (LSS). I will present constraints from Planck and WiggleZ, constraining m~1e-33 eV to 1e-25 eV at the percent level. In the range m\gtrsim 1e-22 eV ULAs may also solve the "small-scale problems" of CDM, and suggest other constraints from LSS and high-z observations, constraining m\lesssim 1e-22 eV to be sub-dominant in DM. Future prospects from CMB lensing, and from Euclid galaxy weak lensing, will make sub-percent constraints out to m~1e-21 eV. Model-dependent couplings between axions and photons provide still other bounds from CMB spectral distortions. Finally, if the inflationary energy scale is high, corresponding to an observable tensor-to-scalar ratio, then CMB isocurvature perturbations provide the strongest constraints on m>1e-24 eV, ruling out ULA dark matter in the simplest inflationary scenarios over the entire range considered, as well as the "anthropic window" for the QCD axion.
Axions: Past, Present and Future

Surjeet Rajendran Stanford University

June 18, 2014

PIRSA:14060025

I will review the theoretical motivations for axion and axion-like-particles. I will then discuss bounds on such particles and highlight ways to experimentally probe them.
Inflationary Gravitational Waves: Recent Developments and Next Steps

Marc Kamionkowski Johns Hopkins University - Department of Physics & Astronomy

June 18, 2014

PIRSA:14060024

The recently reported evidence for the cosmic microwave background signature of inflationary gravitational waves is very tantalizing. I will discuss how the measurement is done, the evidence presented by BICEP2, the interpretation, and some of the criticisms of the arguments presented by BICEP2 that the signal is not dust-dominated. I will then review next steps to be taken with future CMB experiments and with galaxy surveys.
Precision Spectroscopy of Atomic Lithium

Jason Stalnaker Oberlin College

June 17, 2014

PIRSA:14060022

The simplicity of the atomic structure of lithium has long made it a system of theoretical interest. With the development of stabilized optical frequency combs, it is possible to achieve experimental accuracies that provide significant tests of atomic theory calculations as well as a window into nuclear structure. I will discuss an ongoing experimental effort at Oberlin College to measure the energy levels of lithium using a stabilized optical frequency comb.
A quantum network of clocks

Mikhail Lukin Harvard University

June 17, 2014

PIRSA:14060021

By combining precision metrology and quantum networks, we describe a quantum, cooperative protocol for the operation of a network consisting of geographically remote optical atomic clocks. Using non-local entangled states, we demonstrate an optimal utilization of the global network resources, and show that such a network can be operated near the fundamental limit set by quantum theory yielding an ultra-precise clock signal. Besides serving as a real-time clock for the international time scale, the proposed quantum network also represents a large-scale quantum sensor that can be used to probe the fundamen- tal laws of physics, including relativity and connections between space-time and quantum physics. Prospects for realization of such networks will be discussed.
Dark Energy and Testing Gravity

Raman Sundrum University of Maryland, College Park

June 17, 2014

PIRSA:14060020

I will review why the mild acceleration of the Universe poses a major puzzle, the Cosmological Constant Problem, for the connection between gravity and matter, suggesting a possible breakdown in the standard general relativistic and field theoretic description. Thus far theorists have failed to provide any very concrete and testable resolution. I will however discuss some simple theoretical ideas that suggest directions for experiments to lead the way.

Title	Speaker(s)	Date	Talk Type	Info link
Optical magnetometry - From basics to Global Network of Optical Magnetometer for Exotic physics	Nathan Leefer, Szymon Pustelny	2014-06-19	Conference	View details
Free Discussion		2014-06-18	Conference	View details
Search for new physics in atoms: cosmic PNC and variation of alpha	Vladimir Dzuba	2014-06-18	Conference	View details
Ultra-light hidden photons	Jeremy Mardon	2014-06-18	Conference	View details
Axion-induced effects and topological defect dark matter detection schemes	Yevgeny Stadnik	2014-06-18	Conference	View details
Astrophysical and cosmological aspects of feebly-interacting light species	Josef Pradler	2014-06-18	Conference	View details
Cosmological Constraints on Ultra-light Axions	David Marsh	2014-06-18	Conference	View details
Axions: Past, Present and Future	Surjeet Rajendran	2014-06-18	Conference	View details
Inflationary Gravitational Waves: Recent Developments and Next Steps	Marc Kamionkowski	2014-06-18	Conference	View details
Precision Spectroscopy of Atomic Lithium	Jason Stalnaker	2014-06-17	Conference	View details
A quantum network of clocks	Mikhail Lukin	2014-06-17	Conference	View details
Dark Energy and Testing Gravity	Raman Sundrum	2014-06-17	Conference	View details

Format results