Penn organizing meeting on ‘Thermal Noise’ in Pisa – Hobart and William Smith Colleges \
The HWS Update

Penn organizing meeting on ‘Thermal Noise’ in Pisa

Professor Steven Penn of the HWS Physics Department is organizing a meeting on Saturday, Oct. 7 in the Italian city of Pisa.

Gravity wave physicists who are performing research on thermal noise will be attending; the session will include researchers who work with the LIGO observatory in the United States, the GEO observatory in Germany, and the Virgo Observatory in Italy.

The goal of the meeting is to improve communication and collaboration among the researchers and to help coordinate long-term thermal noise research efforts.

Penn also talked about suspension thermal noise at the LIGO Science Collaboration in August in Baton Rouge, La.

The talk focused on his recent work in suspension thermal noise and how it may be lowered in order to increase LIGO's sensitivity to gravity wave events. Penn's work is generously supported by an NSF grant.

Thermal noise, Penn explains, refers to the uncertainty in a measurement caused by thermally activated fluctuations in the measuring apparatus. Recall that temperature is a measure of the average kinetic energy of a body, and thus all objects above absolute zero have a vibrational energy proportional to their temperature. So any measuring device “has a thermally induced vibration that introduces an uncertainty in the measurement.”

“Near absolute zero, thermal noise approaches zero, but it would be very hard to cool LIGO's 4 km interferometer. Instead LIGO has a clever method for concentrating most of the thermal noise at frequencies where we don't look,” Penn said.

Also in August, Penn presented a poster at the World Wide Developers Conference in San Francisco.

The poster, titled “BicoViewer: Using Bicoherence in the Search for Gravity Waves,” described a computer software package he has developed to look at higher-order statistical noise in gravity wave detectors.

“The developers conference was focused on scientific programming this year. It was a wonderful learning experience. Very exciting and energizing,” he said.