Tuesday, November 18, 2014

Voting in Romania



Voting section
I went to Romania to vote.  I actually wanted to support one of the candidates this time! Thanks to Wizz air (15 Euro/flight up to the last minute) it was easier to fly to Timisoara than to figure out how to vote abroad. Coincidentally, we ended up voting in the physics office of the school that our address was assigned to. There were 3 voting booths, a few people, and no waiting line. I was also impressed that stores did not sell alcohol on Sunday (the voting day) because people were supposed to be clear minded.

So, who won? and what do I think of them? Klaus Johannis (Partidul National Liberal). He is a highschool teacher of physics turned politician, which can be taken as one more proof that physicists are smart and can do anything! His election should make the country more open and more connected to Western Europe. There are already a lot of investors from Italy, France, Switzerland and Germany, which lead most of the agricultural sector and most businesses in Romania.  Mr. Johannis is from the German minority of Romania and speaks Romanian with a slight German accent. I found it a bit funny to be listening to him talk. I could almost envision hearing him speak the German translation of his words.

His opponent had been the current prime minister, Mr. Victor Ponta - Partidul Social Democrat, i.e., the socialists/communists. Even though he is young, he is the typical representative of the current political class. Fortunately, this class no longer has strong roots in part due to the large number of foreign investors. So, I have never thought he would win the elections.  He did lie on his resume, and I found it interesting that he was still allowed to candidate. The argument that he did not plagiate because he hired somebody to write his PhD and did not copy himself was particularly funny. Of course, the official version is that he just misused citations for 75% precent of his thesis. Also, he took one course abroad, and then claimed to have a Masters. All this is reprehensible, but then Vladimir Putin also copied his thesis and so did many, many other corrupt leaders. Nobody calls them Dr. Copy-Paste because they are politically too strong to be picked on that way. Furthermore, Ponta is a bit older than me and almost became president and he must have some strength of personality just to be able to stand all the pressure. So, I do believe he does deserves some respect for that and not just media shaming.

Romania is the one country that makes me feel home whether I visit for a few days, a few weeks or a few hours. I still have faith in it. In the long term, I expect progress to continue, the business and agricultural sectors to thrive and property prices to grow. However, just like in the rest of the world, there will be times when things will get worse and times they will get better again. So, I try not to build unreasonable expectations. Had Ponta won, it would have been nothing out of the ordinary - just a continuation of the same corrupt regime, but now people have hope. I pray that they will not be too disappointed too soon.

Disclaimer: I do not own a TV, and I have not been listening to presidential debates. I did hear both Ponta and Johannis speak for about 10 minutes each after I voted. I suppose that means I am not a well informed person, but somehow the trash throwing that the politicians do never seemed worth my time or peace of mind.  

No Alcohol on voting day
Will I move back to Romania? It's unclear.  So far I have consistently tried to be in the country where I thought I could do the most science. I have spent so much time studying that I thought it a pity to not continue, but I am not sure what I will do in the long term.

I close by quoting my brother: "Life is beautiful when you wake up in the morning and for a few minutes you do not know what country you are in today, and when you do not yet know what country you will be in tomorrow". He lives this way. For my side, however, I have mostly been feeling uncertain and afraid instead of excited and looking forward to many next adventures.

Monday, November 3, 2014

Testing Alternative Theories of Gravity with Atomic Clocks

Modelling the Dark Side of the Universe
Most our instruments are built to detect light (e.g., stars, dust, galaxies), and so we still know very little about the dark sector, which comprises more than 95% of the universe and neither emits nor absorbs light. The simplest type possible type of dark matter particles are those represented by a spin zero scalar fields. Scalar fields can arise from not-yet understood physics such as compactified extra dimensions. The Higgs particle is believed to be the first fundamental scalar field ever detected. In cosmology, the initial rapid inflation of the universe is also best modelled by a scalar field called the inflaton, while the quintessence scalar field generates a form of dark energy that may account for the accelerated rate of expansion of the universe. It is reasonable to believe that similar to the visible sector, the dark sector is rich and contains particles of different kinds with various masses.


Alternative theories of gravity and PPN parameters
The solid line corresponds to 10-16 clock stability. 
Einstein's theory of gravity alone cannot account for dark matter or dark energy. Instead, a scalar field that may couple in different ways to different kinds of matter enters the theory of gravitation in addition to the metric tensor of general relativity. This field couples to matter and therefore violates General Relativity. The standard way to describe deviations from General Relativity in weak gravitational fields is via the Parametrized Post-Newtonian (PPN) formalism. The most commonly constrained PPN parameters are 𝛄 and β.

In Einstein's General Relativity 𝛄=β=1. When the scalar field is massless, the 𝛄 and β parameters are constant. The introduction of a mass term causes the 𝛄-parameter to become distance dependent. It is thus natural to expect that PPN parameters may depend on both the distance from and the composition of the mass they are tested around, e.g.,  their value measured around the Earth would be different than around the Sun. The strongest constraint on the 𝛄 PPN parameter comes from the Cassini spacecraft, which limits the size of the parameter around the Sun to 2.3 x 10-5 (1-sigma confidence level). Null results from planetary ephemerides place similar constraints on the  β parameter.

Testing Alternative theories of Gravity with Clocks in Space
Performing accurate timing experiments with satellites carrying state-of-the-art atomic clocks in Earth orbit can test alternative theories of gravity such as scalar-tensor theories. The Hydrogen Maser placed aboard the International Space Station as part of the Atomic Clock Ensemble in Space (ACES) mission is expected to reach  a frequency inaccuracy of 10-16.  

We calculate the gravitational redshift for an eccentric Earth orbit induced by varying PPN parameters and compare it to the one predicted by GR.  We find that a clock with the stability that should be achieved by the ACES mission placed in an elliptical orbit would constrain 𝛄 and β to the 10-6 level (see figure). We take an eccentric orbit with the same parameters as that proposed for the orbit of the originally proposed STE-QUEST satellite.  Choosing an  eccentric orbit makes the signal stronger since the relativistic effects are larger than for a circular orbit due to the higher velocity at perigee.

PPN parameters for general scalar-tensor theories
We compute the PPN parameters γ and β for general scalar-tensor theories in the Einstein frame, which we compare to the existing PPN formulation in the Jordan frame for alternative theories of gravity. Note that there are infinitely many possible frames, but these two frames are the ones that are typically chosen. In the Einstein frame, the Ricci scalar appears alone and the matter fields couple to a conformally related metric, while in the Jordan frame, the scalar field multiplies the Ricci scalar and any matter fields present couple directly to the frame metric. This computation is important for scalar-tensor theories that are expressed in the Einstein frame, such as chameleon and symmetron theories, which can incorporate hiding mechanisms that predict environment-dependent PPN parameters. 

Extended Point Source?
The PPN parameters are typically calculated for a space-time consisting of a point source surrounded by vacuum, which is not accurate for experiments performed around extended objects like the Sun. Instead, we add a parameter that measures how much the exterior gravitational field deviates from that of a point source with the same mass.  To check our assumptions, we recompute the Cassini constraint modelling the Sun as a homogenous sphere instead of a point source for massive Brans-Dicke theories, and find that the 𝛄-PPN  constraint becomes more stringent.

The article this post is based on was led by PhD student Andreas Schaerer.  The paper is published in Physical Review D. I have also written a conference proceeding that describes tests of gravity with space-based atomic clocks and atom interferometers.

Saturday, October 18, 2014

Dear Immigration Offices Worldwide

I do not love you and I have never feigned affection for you, but I somehow I still feel the need to make my feelings clear. I would like more time away from you.  I can understand visiting you once when I move to a new country. However, seeing your representatives and going through the associated tons of paperwork so often is tiring, and, of course, counter-productive. All my energy feels drained after interacting with you. You often fail to see me as human and yet I have to go through this seemingly endless process of registering, reregistering, and re-re-...-registering myself.

Until next time,

Your lawful immigrant who generally submits most documents on time.

What is the origin of the Kreisburo(s)?
My understanding is that careful registration of individuals and their addresses originated in the period before the Holocaust.  It appears that immigration offices are some of the numerous vestiges from that era that exist outside museums. In the past, authorities needed to know the exact address of Jewish individuals so that they could find them and arrest/kill them later, which, while not reassuring, made sense in that political climate.

What will the future bring?
We believe to be better now, but is that true? or is the hatred just focused in other directions? will we ever build a world without wars and so much discrimination in seemingly all directions? I, of course, do not know the answer to these questions, but I believe in the power of information flow, which is made instantaneous by the internet. In the meantime, like in most love-hate affairs, people on both sides have to continue to avoid being bitter, and, in particular, avoid placing blame on the wrong shoulders until the many problems resolve and others appear.

Getting back to today
As long as my paperwork is done, I should not complain. Immigration is a complicated problem. Immigrants keep the economy growing as long as they are controlled and underpaid. It naturally makes sense to continue to keep them that way as long as possible and then blame their condition on the views of the public.

The tons paperwork and the many interviews that sometimes make me feel a cross-bred between a criminal and a moron are good practice - each in its own way. Sometimes, I am interviewed by people who have no understanding of who I am or what I do. At other times, I am interviewed by very kind people who make me feel good about my achievements, and try to solve my often atypical paperwork problems.  The stressful part is not knowing which kind of person will be at the other side of the desk. I try to respect them all. I also understand that they are not to blame and generally have no power to change the laws.

Thursday, October 2, 2014

Bye, Bye Fallanden


Under the rainbow
We'll miss the lake, the mountains, the corn, the swans, the ducks, the fox (dear fox - we've only seen you once, but I have to say you are very pretty and graceful, and even though you destroyed our trash bags on a regular basis you were my favourite neighbour), the hunting lodge, the various parks, and, of course, the house we lived in.  For once, I have very little to say other that I am tired of moving and of not having a home of my own. I suppose the right attitude is to be grateful for the experience, but somehow I am tired of being tired, which may make little sense.

The swans
The corn was about 3 meters high.


On rollerblades
The hunting lodge
The rainbow up the hill




A view of cloudy Fallanden
Edward and the ducks