78 research outputs found
Precision Measurement of Time-Reversal Symmetry Violation with Laser-Cooled Polyatomic Molecules
Precision searches for time-reversal symmetry violating interactions in polar
molecules are extremely sensitive probes of high energy physics beyond the
Standard Model. To extend the reach of these probes into the PeV regime, long
coherence times and large count rates are necessary. Recent advances in laser
cooling of polar molecules offer one important tool -- optical trapping.
However, the types of molecules that have been laser-cooled so far do not have
the highly desirable combination of features for new physics searches, such as
the ability to fully polarize and the existence of internal co-magnetometer
states. We show that by utilizing the internal degrees of freedom present only
in molecules with at least three atoms, these features can be attained
simultaneously with molecules that have simple structure and are amenable to
laser cooling and trapping
Sweeping molecules with light
Many areas of physics—precision measurements, quantum information, and physical chemistry, to name a few—are starting to benefit from the enormous advantages offered by cold and ultracold polar molecules. Molecules have more states, more interactions, and more chemical properties compared to atoms, which make them exciting to study but difficult to tame. In particular, the powerful techniques of atomic laser cooling cannot be naïvely applied to molecules due to their complicated structure. Developments over the past few years have made directly laser cooled and trapped molecules a reality, and now much effort is focused on making these samples larger, denser, and colder—an important step to realizing many of their exciting applications. A careful experimental and numerical study by Truppe et al (2017 New J. Phys. 19 022001) demonstrates a significant improvement and advance in understanding of one of the most limiting steps in laser cooling and trapping of molecules—slowing them from a molecular beam to a near-standstill, with small enough kinetic energy that they can be loaded into a trap
Trapped Ions Test Fundamental Particle Physics
New precision experiments using trapped molecular ions provide an alternative method for determining if the electron has an electric dipole moment
Chi-squared Test for Binned, Gaussian Samples
We examine the χ^2 test for binned, Gaussian samples, including effects due to the fact that the experimentally available sample standard deviation and the unavailable true standard deviation have different statistical properties. For data formed by binning Gaussian samples with bin size n, we find that the expected value and standard deviation of the reduced χ^2 statistic is
[(n-1)/(n-3) ± (n-1)/(n-3)√[(n-2)/(n-5)]√[2/(N-1)], where N is the total number of binned values. This is strictly larger in both mean
and standard deviation than the value of 1 ± (2/(N-1))^(1/2) reported in standard treatments, which ignore the distinction between true and sample standard deviation
Polyatomic molecules as quantum sensors for fundamental physics
Precision measurements in molecules have advanced rapidly in recent years through developments in techniques to cool, trap, and control. The complexity of molecules makes them a challenge to study, but also offers opportunities for enhanced sensitivity to many interesting effects. Polyatomic molecules offer additional complexity compared to diatomic molecules, yet are still 'simple' enough to be laser-cooled and controlled. While laser cooling molecules is still a research frontier itself, there are many proposed and ongoing experiments seeking to combine the advanced control enabled by ultracold temperatures with the intrinsic sensitivity of molecules. In this perspective, we discuss some applications where laser-cooled polyatomic molecules may offer advantages for precision measurements of fundamental physics, both within and beyond the Standard Model
Searching For Fundamental Symmetry Violations With Polyatomic Molecules
The fact that the universe is made entirely out of matter, and contains no free anti-matter, has no physical explanation. The unknown process that created matter in the universe must violate a number of fundamental symmetries, including those that forbid the existence of certain electromagnetic moments of fundamental particles -- moments which are amplified by the large internal fields in polar molecules. We discuss spectroscopic and theoretical investigations into polyatomic molecules that uniquely combine multiple desirable features for precision measurement, such as high polarizability through symmetry-lowering mechanical motions, laser-coolable electronic structures, and exotic nuclei
Probing Fundamental Symmetries of Deformed Nuclei in Symmetric Top Molecules
Precision measurements of Schiff moments in heavy, deformed nuclei are
sensitive probes of beyond Standard Model -violation in the hadronic
sector. While the most sensitive limits on Schiff moments to date are set with
diamagnetic atoms, polar polyatomic molecules can offer higher sensitivities
with unique experimental advantages. In particular, symmetric top molecular
ions possess -doublets of opposite parity with especially small splittings,
leading to full polarization at low fields, internal co-magnetometer states
useful for rejection of systematic effects, and the ability to perform
sensitive searches for -violation using a small number of trapped ions
containing heavy exotic nuclei. We consider the symmetric top cation
RaOCH as a prototypical and candidate platform for performing
sensitive nuclear Schiff measurements and characterize in detail its internal
structure using relativistic ab initio methods. The combination of enhancements
from a deformed nucleus, large polarizability, and unique molecular structure
make this molecule a promising platform to search for fundamental symmetry
violation even with a single trapped ion
Non-resonant cavity for intensity buildup of multiple lasers
A non-resonant cavity to build up laser intensity is modeled, developed and
tested. It can be used for overlapping multiple lasers of different
wavelengths, increasing their intensities by over an order of magnitude while
maintaining good uniformity. It is simple to set up, has flexible optical
characteristics, and is robust against perturbations. The intensity buildup
requires no resonances, and the wavelength dependence of the performance is
limited only by the mirror coatings. The cavity can be used in applications
requiring a spatially-constrained intensity buildup, for example in atomic and
molecular traps.Comment: 15 pages, 11 figure
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