You can see Einstein (front row) and Schrödinger (3rd row). You can also see Dirac (2nd row) between Einstein and Schrödinger.
The purpose of this webpage is to provide a caption to this photo.
Schrödinger and Einstein

 However, Schrödinger's main contribution has been and still is
his wave mechanics. He was interested in standing waves when he
was 8 years old (1895) as can be seen from his
handwritten note. This image was scanned from
this photo collection organized
by Peter Graf.
 Ten years later, in 1905, Einstein formulated his special theory of
relativity based on Lorentz transformations. The question then is
how the standing waves look to a moving observer?
Einstein did not, neither did Schrödinger. They did not have to because they could not imagine a guitar or violin moving with a relativistic speed.
Let us compare Newton and Einstein. After formulating his law of gravitation between two point particles, he started worrying about what happens between two spherical objects with nonzero radii. It took him 20 years for figure out the gravity law between the sun and the earth.
Likewise, Einstein could have studied how the electron orbit in the hydrogen atom would appear to a moving observer. Some years later, J. S. Bell came up with this picture for this problem. However, Bell was presenting an outdated picture.
 In 1927, the hydrogen orbit was replaced by a standing wave. Thus,
the question became how the standing wave appears to a moving observer.
Many people attempted to punish me for asking this kind of heretic question. However, I was not the first one to raise this question. Paul A. M. Dirac was the first one to worry about this problem and continued his interest even during his late years. From 1927 to 1949, he published the following three papers.
 P. A. M. Dirac, Proc. Roy. Soc. (London) A114, 243 (1927).
 P. A. M. Dirac, Proc. Roy. Soc. (London) A183 , 284 (1945).
 P. A. M. Dirac, Rev. Mod. Phys. 21 , 392 (1949).
 On the other hand, Dirac made no attempts to combine these three papers
into one.
 In his 1945 paper on harmonic oscillators, he introduces
the time variable, but makes did not give a physical interpretation
to this variable in terms of the cnumber timeenergy uncertainty
relation he introduced in his 1927 paper.
 In his 1949 paper, he introduced the lightcone coordinate system, but
he never mentioned his 1945 paper on the harmonic oscillators.
 Also in his 1949 paper, Dirac said the construction of relativistic quantum mechanics is the construction of representations of the Poincaré group. However, for this purpose, he never attempted to use the harmonic oscillator wave functions he introduced in his 1945 paper.
 In his 1945 paper on harmonic oscillators, he introduces
the time variable, but makes did not give a physical interpretation
to this variable in terms of the cnumber timeenergy uncertainty
relation he introduced in his 1927 paper.
 Dirac's papers are like poems, but Dirac never attempted to use
diagrams to illustrate his ideas (physical or mathematical). It is fun
to translate those papers into cartoons. Using those cartoons, it is
straightforward to combine them to produce the quantum mechanics of
harmonic oscillators consistent with the Lorentzcovariant world.
Click here for the cartoons.
The question is whether it is necessary to introduce physical principles not in known in quantum mechanics or special relativity.
 The most pressing question is how to Lorentzboost boundary
conditions. The Bohr radius is the space separation between
the proton and electron. If it is Lorentzboosted, it
picks up a timelike component.
 The timelike separation does not exist the present form of
quantum mechanics. However, according to Einstein, this
variable clearly exists. In his article on Einstein,
Heisenberg confesses
he did not understand the issue of
simultaneity. If simultaneous events are spaceseparated,
they do not appear simultaneous for a moving observer.
 I was once brutally punished by Phys. Rev. referees and by one
of the editors for mentioning this variable, but I am not guilty
of introducing this variable. Read the paper
Feynman published in 1971 with his students. They said there
is a timelike separation between the quark inside a hadron. They
also say they will drop this variable because they did not know what
to do with it. Indeed, Feynman was
my savior in the early stage of my professional life.
Dirac and Feynman, in Jablonna near Warsaw in July (1962). Photo from the Caltech Photo Library. In order to express my respect for them, I visited the same place in 2013 and had this photo.  In his 1927 paper, Dirac said this spacetime asymmetry makes it difficult to
construct quantum mechanics consistent with relativity. In his 1945
paper, Dirac wrote down a Gaussian distribution for both space and
time variables in his attempt to construct harmonic oscillator
wave functions in the Lorentzcovariant world.
However, Dirac did not attempt to specify his time variable as the timeseparation variable. Neither did he attempt to associate this Gaussian time distribution with the cnumber timeenergy uncertainty relation he discussed in his 1927 paper.
 Click here for Dirac and Feynman,
and for their conflicts and resolutions.
The question most cruel to theorists is whether the resulting theory can explain what happens in the real world. Click here for a story.
Wigner's sister became Dirac's wife. I met all three of them.  The timelike separation does not exist the present form of
quantum mechanics. However, according to Einstein, this
variable clearly exists. In his article on Einstein,
Heisenberg confesses
he did not understand the issue of
simultaneity. If simultaneous events are spaceseparated,
they do not appear simultaneous for a moving observer.
 As for the lack of timelike excitations, it is totally
consistent with Wigner's O(3)like little group for massive
particles. Wigner's little groups dictate the internal spacetime
symmetries of particles in the Lorentzcovariant world. For
a massive particle, such as the proton, it is enough to worry
about spacelike excitations.
 Click here for a
1979 paper on this subject. I am one of the three authors
of this paper, and I was not as knowledgeable as I am today.
We forgot to mention there Wigner's little group while
the entire subject was about this group. It is a pleasure to
see I kept growing up since then, and I hope I am still growing up.

Click here to
see where Wigner's little group stands in understanding
standing waves in Einstein's world.
 As for the timeseparation variable, it clearly exists. Yet, we do not know how to measure it in quantum mechanics. If we do not measure the existing variable, it causes a rise in entropy. I was very fortunate to be in a position to publish a paper on this subject with Eugene Wigner. Click here for the paper.
 Click here for a
1979 paper on this subject. I am one of the three authors
of this paper, and I was not as knowledgeable as I am today.
We forgot to mention there Wigner's little group while
the entire subject was about this group. It is a pleasure to
see I kept growing up since then, and I hope I am still growing up.
 Based on what I said above, I can now construct
this historical chart.
 In constructing this chart, Dirac was not enough, and
the story is the same for Feynman and Wigner. We have to
combine all three of them. Like to see how they are combined?
Click here.
 We know how the hydrogen atom appeared to us 100 years ago.
How does it look these days?
Click here for the evolution of the hydrogen atom.
 Click here for Einstein
and Bohr.
In order to make this page more meaningful, I visited Schrödinger's Vienna while I was in Europe in June (2013). I went to the Institute of Physics of the University of Vienna to see how Schrödinger wrote his papers.
Here are some of the photos I took there.
 Entrance to the Institute at
5 Boltzmanngasse. Here is a closeup view.
 Erwin Schrödinger Zimmer. His office
is now used as a gathering place for graduate students. It was a
great pleasure for me to have a
photo with them in this room.
 Schrödinger Auditorium was closed when
I was there.
 Schrödinger's Notes were kept in
the library room belonging to the Austrian Central Library of Physics.
Dr. Peter Graf was kind enough to show me the
Schrödinger collection there. From these
pages, you can see how Schrödinger was meticulous in doing physics.
 Schrödinger Photo Collection is available
for purchase at this library. When I have a clear understanding of
the applicable copyright laws, I hope to post many photos to this website.
 In constructing this chart, Dirac was not enough, and
the story is the same for Feynman and Wigner. We have to
combine all three of them. Like to see how they are combined?
Click here.
 You may also be interested in my Vienna page which I constructed in 2008. Vienna is known as as a great music city. I would like to add more photos when I have time. In the meantime, please send me photos you like to show to others. I will be very happy to include them.
Y. S. Kim (September 2013)
copyright@2013 by Y. S. Kim, unless otherwise specified. Photos are from from his own collection or from the public domain unless otherwise specified.

 Click here for his home page.
I received my PhD degree from Princeton in 1961, seven years after high school graduation in 1954. This means that I did much of the ground work for the degree during my high school years.