On the cosmology of Alexander Vilenkin of Tufts University


Alexander Vilenkin, Director of the Institute of Cosmology
Tufts University (STEM), Medford, Massachusetts

Articles: The Beginning of the Universe
ArXiv (121): Quantum cosmology, eternal inflation, and swampland conjectures, with Georgios Fanaras, 2023; Arrows of time and the beginning of the universe (PDF), 2013

“The main difference from the Hartle-Hawking wave function is that the amplitude for the semiclassical variables (the radius of the universe and the homogeneous component of the inflaton field) is given by a special prescription (using DeWitt’s minisuperspace metric), rather than by the instanton action, as in Eq. (22).”

Hessian eigenvalue distribution in a random Gaussian landscape
BooksMany Worlds in One: The Search for Other Universes
CV  Google Scholar Homepage Twitter Wikipedia YouTube  

Fourth email: 23 February 2023

Dear Prof. Dr. Alexander Vilenkin:

I have just started to digest your new article. You are constantly pushing these concepts in new ways. I had also been trying to grasp the work of Jaume  Amorós, Jaume Haro and Supriya Pan, The Peebles–Vilenkin quintessential inflation model revisited,  Eur. Phys. J. C79,505 (2019). https://doi.org/10.1140/epjc/s10052-019-7012-0

Is there a better definition of the inflaton (as currently defined by Wikipedia) or the inflaton field?  https://81018.com/inflaton/#Vilenkin

Nobody should be absurd to themselves, but we should give Alan Guth his space.

When we are wrong, integrity is more important so we acknowledge our mistake, learn a little, and move on. Having had to defend his thesis for a lifetime, Alan Guth can be forgiven if he is holding on to his concept of inflation. Yet, his Inflationary Epoch was so unique, he’s had a long rough road and we all should give him his a little peace. Life is short and none of us will be around too much longer. Everybody else should bend and gladly entertain swampland conjectures. Our imaginations are wonderful things.

Thank you.

Warm regards,


Third email: 11 February 2021

Dear Prof. Dr. Alexander Vilenkin:

Long, long ago, I lived in Melrose, had in office in Somerville, and even had friends on the faculty and board of Tufts, but I have never visited the Institute of Cosmology. Might it be possible the next time I come to Boston? I have property in Bremen, Maine (out on the coast from Damariscotta) so I come to town on occasion.

Though late in life to kindle an interest in cosmology, that path has been quite idiosyncratic.

When Stephen Hawking’s colleague and friend, Neil Turok said the big bang is wrong, it seemed that finally there would be a more robust search for an alternative theory. In my early research, I found the Cambridge University 1999 Structure Formation in the Universe conference. And, I see that you were there! It seems to be one of the first conferences to have all the key players and to ask, “Isn’t there a better theory?”

There has just been so much investment into the infinitely-hot big bang, it is hard to get the scholarly community to begin to engage other possible concepts. For example, Harvard’s David Layzer proposed testing Lemaitre’s 1927 cold start. Anthony Aguirre followed up, but nothing quite gelled. At about the same time Layzer was asking questions, Penzias-and-Wilson’s declarations about the cosmic microwave background radiation (CMBR) gave the big bang’s in finitely-hot start a sense of substance and what followed is an arduous history.

It appears that at no time has anybody proposed that the universe begins with the Planck base units and that something like an infinitesimal “Planck Sphere” manifests. Taking the numbers as given by Max Planck, this infinitesimal thing has tremendous energy given Planck Charge and the “electromagnetic radiation” operating at the speed of light. It has extraordinary density given the mass/length ratios, and a remarkable expansion rate given Planck Time. On its face, that is 539 tredecillion spheres per second. Certainly it would seem to describe what some might call a big bang, yet these spheres are many orders of magnitude smaller than neutrinos. Perhaps these could be identified as dark energy and dark matter, even a new aether and the simple basis for homogeneity and isotropy.

In these days there are many articles with many co-authors. I have kept this draft of a future posting brief in hopes that people with your depth might take a look and suggest additions or-deletions. Might you take a look?

https://81018.com/instance/ Thank you.

Warm regards,


Second email: 16 January 2019 in the evening

You are all on this homepage and your individual pages have also been updated:
Vilenkin: https://81018.com/2018/10/13/vilenkin/
Kiefer: https://81018.com/2018/09/20/kiefer/
Adler: https://81018.com/adler/


I look forward to your feedback. Thank you.


Second email: 16 January 2019 in the morning

Dear Prof. Dr. Alexander Vilenkin:

Thank you for your scholarship and the pursuit of intellectual integrity. Please excuse me if my questions seem in any way too direct or offensive:

  1. Is big bang cosmology still the best model?
  2. Isn’t Newton’s absolute space-and-time assumed, and is it the best model?
  3. Could there be a natural inflation from the Planck scale? The numbers using base-2 are interesting: https://81018.com/chart/
  4.  Could the thrust originate within the dimensionless constants, especially from light — https://81018.com/c/ and the Planck Charge? https://81018.com/thrust/

Thank you.
Most sincerely,

P.S. I write to scholars. I have also written about these four questions to Claus Keifer (Cologne) and Stephen Louis Adler (IAS) and all three of you are referenced on this homepage.

First email: Saturday, October 13, 2018

Dear Prof. Dr. Alexander Vilenkin:

In doing a survey this morning of your body of work, particularly the idea of quantum creation from a quantum vacuum, the mechanisms of symmetry breaking, phase transitions and topological defects (and cosmic strings), I know you will think that what we are doing is just foolishness. It all started back in a New Orleans high school, so I would love somebody of your depth and breadth to get us back within the mainstream.

We just started out so naively; we’ve had to forge our own way.

We have five assumptions about this universe: (1) the Planck base units are the best numbers to begin a study of the universe, (2) Length-and-Time and Mass-and-Charge are the basic four concepts, (3) thrust is given within light, within the never-ending, never-repeating dimensionless constants that define those base units, and also within Planck Charge, and (4) an infinitesimal sphere best describes the first manifestation of physicality and we call it a plancksphere. The thrust and the spheres become the expansion; the doublings noted as base-2 is essentially tracking the expansion.

One of our summaries of those statements is here: https://81018.com/2017/10/16/eight/

We started with Zeno’s paradox and simple geometries and it got out of control over the years!

Might we hear from you?

Most sincerely,


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