Scientists are certain that dark matter’ exists. Yet, after quite 50 years of searching, they still haven’t any evidence for the mysterious substance.
University of Delaware’s Swati Singh is among alittle group of researchers across the dark matter community that have begun to wonder if they’re trying to find the proper type of dark-matter.
“What if dark matter is far lighter than what standard particle physics experiments are looking for?” said Singh, an professor of electrical & computer engineering at UD.
Now, Singh, Jack Manley, a UD doctoral student, and collaborators at the University of Arizona and Haverford College, have proposed a latest way to search for the particles which may structure substance by repurposing existing tabletop sensor technology. The team recently reported their approach in-a paper published in Physical Review Letters.
Co-authors on the paper include Dalziel Wilson, an professor of optical sciences from Arizona, Mitul Dey Chowdhury, an Arizona doctoral student, and Daniel Grin, an professor of physics at Haverford College.
No ordinary matter
Singh explained that if you add up all the items that emit light, like stars, planets and interstellar gas, it only accounts for about 15% of the matter within the Universe. the opposite 85% is understood as dark matter. It doesn’t emit light, but researchers realize it exists by its gravitational effects. They also realize it isn’t ordinary matter, like gas, dust, stars, planets, and us.
“It might be made from black holes, or it might be made from something trillions of times smaller than an electron, referred to as ultralight dark-matter,” said Singh, a quantum theorist known for her pioneering efforts to push-forward mechanical dark matter’ detection.
One possibility is that dark matter is formed from dark photons, a kind of dark matter that might exert a weak oscillating force on normal matter, causing a particle to maneuver back and forth. However, since dark matter’ is everywhere, it exerts that force on everything, making it hard to calculate this movement.
Singh and her collaborators said they think they will overcome this obstacle by using optomechanical accelerometers as sensors to detect and amplify this oscillation.
“If the force is material dependent, by using two objects composed of various materials the amount that they’re forced are going to be different, meaning that you simply would be ready to measure that difference in acceleration between the 2 materials,” said Manley, the paper’s lead author.
Wilson, a quantum experimentalist and one among the UD team’s collaborators, likened an optomechanical accelerometer to a miniature implement . “It’s a vibrating device which, thanks to its small size, is extremely sensitive to perturbations from the environment,” he said.
Now, the researchers have proposed an experiment employing a membrane made from silicon nitride and a hard and fast beryllium mirror to bounce light between the 2 surfaces. If the space between the 2 materials changes, the researchers would know from the reflected light that dark photons were present because the silicon nitride and beryllium have different material properties.
Collaboration was a key a part of developing the experiment’s design, consistent with Manley. He and Singh (theorists) worked with Wilson and Dey Chowdhury (experimentalists) on the theoretical calculations that went into the detailed blueprint for building their proposed tabletop accelerometer sensor. Meanwhile, Grin, a cosmologist, helped shed light on the particle-physics aspects of ultralight dark-matter, like why it might be ultralight, why it’d couple to materials differently and the way it’d be produced.
As a theorist, Manley said the chance to find out more about how devices work and the way experimentalists build things to prove the theories that he and Singh develop has deepened his expertise while simultaneously widening his exposure to possible career paths.
A growing body of work
Importantly, this latest work builds on previously published research by the collaborating teams, reported last summer in Physical Review Letters. The paper, including contributions from former UD graduate-student Russell Stump, showed that several existing and near-term laboratory-scale devices are sensitive enough to detect, or rule out, possible particles that would be ultralight dark matter’.
The research reported that certain sorts of ultralight dark matter would connect, or couple, with normal matter in-a way that might cause a periodic change within the size of atoms. While small fluctuations within the size of one atom could also be difficult to note , the effect is amplified in an object composed of the many atoms, and further amplification are often achieved if that object is an acoustic resonator. The collaboration evaluated the performance of several resonators made from diverse materials starting from superfluid helium to single-crystalline sapphire, and located these sensors are often wont to detect that dark matter-induced strain signal.
Both projects were supported partially through Singh’s funding from the National Science Foundation to explore emerging ideas around using state-of-the-art quantum devices to detect astrophysical phenomena with tabletop technologies that are smaller and fewer expensive than other methods.
Together, Singh said, these papers extend the body of labor on what’s known about possible ways to detect dark matter’ and suggest the possibility of a new gen of table-top experiments.
Singh and Manley are working with other experimental groups, too, to develop additional tabletop sensors to seem for such dark matter or other weak astrophysical signals. They are also actively cultivating broader discussions on this subject within the dark matter and quantum sensors communities.
For example, Singh recently discussed transformational instrumentation advances in particle-physics detectors at a virtual workshop organized by the Department of Energy’s Coordinating Panel for Advanced Detectors (CPAD). She also presented these results at a special workshop during the American Physical Society’s April meeting.
“It’s an exciting time, and that i am learning tons from the questions posed by scientists from diverse backgrounds at such workshops,” said Singh. “But it’s worth noting that my most original research ideas still begin of questions posed by curious students.”
The findings are reported on Physical Review Letter