Time, complexity, entropy, and the multiverse

FQXi, the Foundational Questions Institute, held a multidisciplinary meeting investigating the Nature of Time in Scandinavia August 27 – September 1, 2011 (Figure 1). FQXi promulgates original thinking and research on fundamental questions in physics and cosmology through research grants and essay-writing contests on topics such as “The Nature of Time,” and “Is Reality Digital or Analog?”

Figure 1. Multidisciplinary topics covered at the FQXi Time Conference

Time is familiar in the sense of the three space dimensions and the one time dimension around which human affairs in the physical world are organized. Additionally, each person has a subjective and identifiable relationship to time, even though this may be little more than a convenient construct. In science, time has been developed to the greatest degree in physics and cosmology, and in the philosophy of science. Other fields too are starting to consider time more robustly, including complexity, biology, and computation.

The conference addressed the issue of the arrow of time from many perspectives. While most fundamental laws of nature are time-symmetric, some areas have a time arrow flowing in one direction such as thermodynamics, quantum theory, radiation, and gravity. This can be problematic to explain. A suggested analysis structure involving the trade-offs between complexity and entropy as systems evolve over time served as a useful model for analyzing different aspects of time throughout the meeting.

Future of physics

The future of physics and cosmology was discussed at length at a recent conference held by the foundational physics research institute FQXi, particularly considering what may be ultimately possible and impossible for physics.

Theoretical physics has been progressing in many areas but there is still a strong need for observational evidence and/or alternative theories to support or disprove the existing ones. Luckily, much anticipated experimental evidence may be available in the next few years from the Large Hadron Collider (LHC), Planck Satellite, Pierre Auger Observatory and other observational astrophysics projects. For example, the Planck Satellite aims to look farther back in time than has been seen so far with the Cosmic Background Explorer (COBE), earlier than the 400,000 year old universe. It is theorized that B-modes, primordial gravitational waves from inflation, may be visible in the very early universe, which would provide additional proof of the inflationary phase occurring directly after the big bang.

Composition of dark energy to be known soon?
Another specific example for which observational evidence may be obtained in the next few years is regarding the composition of dark energy, whether it is vacuum energy made up of axion particles as one multiverse theory predicts or quintessence made up of supersymmetric WIMPs.

Many outstanding physics questions
Some other key issues are how our universe was created in the first place (a quantum theory of creation), proof for multiverse theories and possibly detecting bubble universe collisions, more about post-big bang inflation, why there is so much more antimatter than matter (the antimatter problem), why the weak force is 10³² times stronger than gravity (vs. say a more acceptable 3-4 orders of magnitude; the hierarchy problem), the existence, size and parameters of any additional dimensions of space, not to mention the usual unification of general relativity and quantum mechanics in a quantum theory of gravity, and finally the vexing Boltzmann brain problem, that consciousness could potentially arise from nothing but quantum fluctuations.

Next-gen astrophysics tools critical
Much progress has been made with accelerators, space-based telescopes, terrestrial array telescopes, and adaptive optics but the next era of astrophysics tools could be even more revolutionary. Accelerators are an expensive $5 billion or more and take years if not decades for fundraising, permitting, building and rendering operational. One alternative could be different kinds of accelerators which are smaller, quicker and cheaper to build, notably plasma wakefield accelerators, laser accelerators, and benchtop accelerators. Another way for tools to evolve could be with computational astrophysics and simulations such as MICA's Newtonian N-body simulation (featured by UgoTrade). As computing power continues to grow, accelerator and telescope datasets could be the inputs to large-scale simulation, prediction and test. As nearly every other science has moved into informatics and rigorous math-based prediction, simulation and experimentation, so too could astrophysics, fostering much quicker cycles and a tighter linkage between theoretical and experimental physics.

The FQXi community
Curiosity-driven physics researchers, especially those investigating risky areas on the boundaries of institutional acceptance are encouraged to apply for FQXi grants, and those understanding the value of fundamental physics research funding are encouraged to participate as donors and in the FQXi website community.

NOTE: The author is an advisor to FQXi.