Hello again. Last time I wrote a newsletter was about a year ago where I was a new member of the GraWIToN project. The first time was about introducing myself, speaking about the project in a general manner since it was very new to me. But now it is possible to speak about something more specific after controlling all the different aspects of my research.

In fact, my research work is composed of two different parts with two different laboratories in two different countries. The first laboratory is at BOOSTEC company in collaboration with LGP INP/ENIT, that is an affiliation of the Federal University of Toulouse in France. In this Laboratory, I am working on the thermal and thermo-elastic behavior of silicon carbide (SiC) optical components under two different temperature conditions “room temperature” as in Advanced VIRGO and “cryogenic temperature” for the third generation gravitational wave detector “Einstein Telescope ET”.

Furthermore, the second laboratory is at EGO site in Italy where I am studying the optical behavior of SiC composed of optical characterization and optical simulation. The optical characterization and the optical simulation are performed also under the same temperature conditions to measure scattering and evaluate the intensity of this scattering respectively.

Now, after one year of understanding the subject, it is possible to set the methodology of the simulation work in this thesis which is the essential part for investigating the behavior of SiC baffles.

This methodology illustrates the links between all the experimentation and simulation works. So as a quick explanation, optical experiments allow us to characterize the material (SiC) and to identify the necessary parameters needed for the optical simulations. This allow us to evaluate the flux of the scattered light, which is used as an input in the thermal analysis to study the temperature variation and distribution on the baffles. Hence, after calculating the thermal field, it is introduced as an input to the thermo-elastic analysis to study the deformation of these baffles due to the thermal stress.

The preliminary results of this methodology showed that SiC is a very good candidate at both temperatures “room 293 K and cryogenic 70 K”, however, the investigation is still progressing towards lower temperatures such as 20 K.

Concerning the optical characterization, the preliminary results were only at room temperature and as a conclusion after comparing several samples of SiC and Stainless Steel 304, SiC-CVD has proved that it is the very promising material for our application. However, for the cryogenic temperature, an apparatus is still being discussed with all the necessary optical components needed and it will be ready for the second secondment that is six months starting from next October at EGO Italy.

Some preliminary results of the temperature variation on Stainless Steel 304 AR-coated baffles (AdV) and Silicon Carbide (SiC) for ET at two different temperature conditions (room and cryogenic temperatures). A poster also presented these results during the GWADW 2016 conference at Isle d’Elba in May 2016.

The detection of gravitational waves was a shocking and astonishing news to me at the same time. Despite the fact that my current research was not involved in this phenomenal moment. It gave me a huge boost of motivation to achieve the goals of my research for the ET and work on the constraints and challenges of the future gravitational wave detectors. I am so lucky to be a part of this ongoing field of research.

"We have detected gravitational waves, we did it!". I was sitting in a room, filled with enthusiastic physicists and journalists, at the Albert Einstein Institute in Hannover, Germany, listening to these winged words from David Reitze via a live stream of the press conference taking place in Washington, DC. For me it was a very happy and emotional moment.

As the advanced LIGO (Laser Interferometer Gravitational-Wave Observatory) upgrade was already finished and the two observatories were in commissioning mode when I started to work in the field, I cannot say I contributed anything to this achievement. But my emotions were not rooted in any personal work or success, but in the long journey the field of gravitational waves and the LSC-Virgo collaboration had gone through to finally step over the threshold where the observatories were astronomically useful. In particular, I was moved by thinking about the many individuals in the collaboration that have founded the field, spent decades building and improving gravitational wave observatories, and managed to convince fund raisers that they were able to build these modern wonders of high precision length measurement devices. Now their creation was evidently successful, and their believes and hard work were proven correct and worthwhile. However, I must admit that I was partly happy for personal reasons as well. I was happy for having the fortunate honour of being a member of the team making this historical first direct detection of gravitational waves. I was happy for the opportunity of being a part of the collaboration for the interesting time to come. And I was happy for finally being allowed to talk about the detection we kept a secret for so long while the data was being thoroughly analysed.

Since I were working in Hannover, Germany, at the time of the announcement, and since I do not speak German, I missed out on most real life outreach opportunities. Instead, I tried to be active on social media, and I was also interviewed over Skype by a Swedish local newspaper, which was a new and interesting experience for me.

With the first direct detection of gravitational waves, one huge milestone is reached, but the era of gravitational wave astronomy has just begun. To observe gravitational wave events more frequently, and to better locate the sources on the sky, we need to improve the current observatories, have more observatories in operation simultaneously (Virgo and KAGRA are soon operational, and LIGO-India is hopefully operational in a few years), and keep working towards building even better ones in the future.

This is where my work comes in, which is aiming at improving the current gravitational wave observatories, as well as contributing to the design of future observatories. One technique that will be used for improving future detectors is frequency dependent squeezed light, which offers an increased sensitivity in the whole frequency band where the current detectors are designed to look for gravitational waves. The name squeezed light can be a bit misleading, as the light itself is not squeezed, but its quantum noise. If the phase noise (noise in photon arrival times) is squeezed (reduced phase noise), the amplitude noise (noise in photon energy) is anti-squeezed (increased amplitude noise), and vice versa. Since gravitational wave detectors are limited by amplitude noise for low frequencies, and phase noise for high frequencies, frequency dependent squeezed light could be used to reduce the limiting noise over the whole frequency band. To create this frequency dependence, we use a so called filter cavity.

An ideal laser source has a Gaussian intensity distribution. However, optical defects and mode mismatches between the optical systems can transform the near ideal laser beam into some new spatial distribution. We usually describe the laser beam in terms of Hermite-Gauss or Laguerre-Gauss modes, where the ideal Gaussian beam is described by the fundamental mode or zeroth-order mode. For describing defect beams we add some Higher Order Modes (HOMs) as perturbations to the fundamental mode. However, these HOMs pick up phases different from the fundamental mode as they propagate through the optical system. My current main project is to investigate if this could transform squeezed light into anti-squeezed light, which would lead to extra noise. Furthermore, I am investigating if the sensitivity to optical defects and mode mismatches could be reduced by injecting squeezed HOMs, and if we could avoid the risk of the squeezed HOMs becoming anti-squeezed as they travel through the gravitational wave detector.

Hi, my name is Akshat Singhal and I belong to Delhi, India. I graduated with M.Sc. in Mathematics and Scientific Computing from Indian Institute of Technology, Kanpur in 2014. During my undergraduate days, I was involved in amateur astronomy for about five years, where I led making of first of its kind planetarium and a 14-inch optical observatory. This got me attracted towards observational physics and I joined Gravitational waves community in IUCAA, Pune. I worked as Junior Research Fellow in electromagnetic followup of gravitational waves for a year before receiving a call from Marie Curie project GraWIToN. We are a group of 14 young researchers coming from different parts of the world and will be working on different specialisation with different partners of GraWIToN in Europe for the next generation gravitational wave detectors. I will be working on data analysis of continuous sources of gravitational waves under the umbrella of one of the finest researchers in the field in University of Rome, la Sapienza Italy.

Currently I am studying in Gran Sasso Science Institute, L’Aquila. It is a newly build institute under INFN where I will be having my necessary coursework before I could shift to Rome to start working on my thesis. I received a very warm welcome here. The staff and faculty here are very friendly specially our coordinator Prof. Francis Vissani. We were given an introduction of all the research done here and a tour to National Laboratory of Gran Sasso Lab. It is the biggest underground laboratory where some of the biggest particle physics experiments are carried out, which are changing the way we do physics. I visited the lab many times and every time it is a new learning experience for me. Lectures in GSSI are given by guest lecturers from other universities on astroparticle physics. Good for me that the lectures are in English language. It is almost mandatory in Italy to learn Italian language as people mostly don’t speak English. Some of the lectures here were the best lectures I ever had, specially the one on General Relativity by Prof. Salvatore Capozziello and on Standard Model by Goran Senjanovic. Unlike the exam policy in India, here exams have no deadline and you often have choice on a what topic to present your exam. I learned a lot here, made some good friends at GSSI.

During coursework in my free times, I often visit University of Rome to meet my supervisor Dr. Paola Leaci, to learn basics of my work in directed search of gravitational waves from binary pulsars. For this I am working on Snag, which is a Matlab data analysis toolbox for gravitational waves data. This toolbox is developed by Prof. Sergio Frasca, who is one of the pioneer in this field. With the help of my supervisor and Dr. Cristiano Palomba, I am currently learning how the software works, how can we use it to inject signals into the noise and how can we extract it back. This way we can analyse the effects of various modulation of the signal before it reaches the earth and how can we correct them to extract meaningful physics of the dynamics of the system. We have analysed the limitations of the current method and how the uncertainties in the directed search affect the detection of the signals. It is good to work with this team and there is a lovely work environment here. Last Christmas we had lunch together with the entire team where I had chat with everyone, including Prof. Fulvio Ricci, the spokesperson of VIRGO.

GraWIToN organises training schools with its partners, which aims to train the GraWIToN students in multi-disciplinary fields for a broader vision in gravitational waves search field. As I joined this project lately, I missed the first GraWIToN school, however I have attended both the school since. My first school was the Data analysis school in L’Aquila, immediately after I joined GSSI. This was the first time I met all the other GraWIToN students, and we had a good chemistry between us. Often after day’s end to the schools and conference we hung out together, socialised, shared jokes, shared our native cultures and enjoyed a good time. The last school was at Birmingham on lasers and optics. These schools have variety of lectures and hand-on workshops which gave us exposure to complex science and engineering behind overwhelmingly sensitive detector.

Then came the breakthrough news. The announcement of the confirmation of the detection named GW150914. This was a game changer, it changed world’s view towards working of the detectors and existence of gravitational waves, the research received worldwide attention from the scientific community and massively by general public as well and to a certain extend it affected the life of people involved in this field. It will be an understatement if I say that it brought a big change in my life. The media reacted very positively and I received instant fame from all around, despite the fact that I was just a toddler, standing on the shoulder of giants in this field. To be honest, often decisions of going towards research rather than industrial jobs are not very popular and raises quite eyebrows. However, a lot of people now started considering them as a possibility after the detection, due to its popularity and I am glad that I was able to encourage some of them towards it. Soon after this detection, we had a conference to discuss the future impact of this detection. There I got the chance to meet a lot of great researchers behind this experiment, all of them were excited and so was I. Very few people are lucky enough to get such a boost in the beginning of their research career.

One of the most important goal of GraWIToN is to give attention to the public outreach. After the news of detection, a lot of people had several queries about the discovery. Astronomy Society of India had organised a general public forum where they could discuss their queries with the people involved in the field, I took part in it and it was exciting to see the response. My undergrad institute, IIT Kanpur, invited me to give a Skype talk on this news and its importance, which was attended by around 200 students. Other than this, there were some common active forums on social media like Quora, Google groups, Facebook where were I tried to answer their curiosity. Surprisingly or not so surprisingly a lot of people were curious to know if the discovery has any connection with time travel or interstellar travel. Then on May 9th one of the rare astronomical event was visible, the transit of the Mercury. It was completely visible from Europe and as an astronomer I was very excited. I convinced our director Eugenio Coccia to organise the event at GSSI for public viewing. We asked 2 astronomers from Observatory of Teramo to assist us with safety equipment and tracking telescope and we were prepared with our setup on the day of the event. Sadly we couldn’t show anything because the clouds cover was followed by showers. We hardly had 10 minute window, but it was not enough.

So far in this project, I learned a lot and enjoyed my journey. Hopefully soon I will be able to contribute more to the subject. In the end I would like to thank Michele Punturo, Elena Cuoco, Erika Morucci for their constant support and all the behind the scene effort, to be there whenever we need their help.

“Ladies and gentlemen, we have detected gravitational waves. We did it!” https://www.youtube.com/watch?v=vd1Pak5f6GQ

These words by LIGO Laboratories Director Dave Reitze will surely make the history of science. They are still echoing in my head as I remember the press conference, broadcasted from Washington DC, I watched in Glasgow on 11 February 2016. It is hard to underestimate this event, when recounting my last months as a GraWIToN gravitational wave researcher. On 14 September 2015, four mirrors on the Earth were imperceptibly shaken by a couple of black holes far deep in the universe, which fell into each other billions of years ago.

After a few seconds, computers carefully programmed over years, by scientists all over the world, began to elaborate the information. Three minutes later, an email alert was sent and in a matter of few hours about a thousand of people got the news: there was a potential gravitational wave signal!

This is where things got really exciting. In the following weeks, as it was becoming clear inside the LIGO-Virgo Collaboration that the signal was real and not an artefact of some kind, we realised we were the keepers of a big secret, one the world should not know about until the paper would be published. Why? Because if data leaked before we were 100% sure, the credibility of the collaboration would be harmed. Also, it was important that the attention was maximum at the press conference, where the funding agencies could be properly acknowledged. Were the news to be broken before the press conference, that would have lowered the hype about the discovery.

I got to see behind the scenes of all this, and it was amazing: the telecons, the palpable excitement in the corridors, the meetings in unusual rooms to divert non-LVC colleagues’ suspicion. The ritual question meeting someone new in the department: “Are you in the LVC?”

For a matter of weeks, I did not make it into the author list, but being part of the process was really incredible. One thing I realised is how “human” an event like this is. Even though there are procedures to follow and cold hard numbers to look at, people will argue and get passionate about things!

All this gave me a lot of motivation to proceed with my research in Glasgow, looking into optical properties of materials for the mirrors of next-generation gravitational wave detectors. I was lucky enough to have the opportunity to present my work in a poster at the Gravitational Wave Advanced Detectors Workshop (GWADW) 2016 on the beautiful Isle of Elba, in Italy.

There was much more interest than I expected in the work done by my group on coatings, and a lot of people came to speak to us. It is pleasant to know that other scientists regard your work as important and needed for the advancement of the field. ­I learnt a lot during the workshop, and had the occasion to network with new people and reinforce the network with others.

Among other trips, I also spent four weeks in Germany working at the Albert Einstein Institute in Hannover, as one of the secondments that the GraWIToN project encourages to foster collaboration between partner institutions. It was a great experience to get to see a different academic culture and work with some of the finest scientists in the field. After much travelling, it is nice to be back in my beloved lab.

But the GraWIToN’s life never settles: soon I will leave for another secondment in England. Immediately after, a LVC (LIGO-Virgo Collaboration) meeting, one of the biggest events in our field, will be hosted in Glasgow. Then, in September, a GraWIToN School.

Seems like there will be a lot to talk about in the next newsletter! See you soon