The definition of a regular crystal is an arrangement of atoms in repeated three-dimensional patterns, called a lattice (see Fig. 1). These patterns repeat again and again along their lattices in space; while time crystals duplicate their patterns through space and time. In other words, they are essentially four-dimensional crystals, and they do not actually ever reach the equilibrium which is the time in which they would stop. The time crystals are designed to be inherently unstable, breaking the symmetry of time, resulting in atoms that are in perpetual motion.
Figure 1. A basic lattice structure of different atoms. Source: Wikimedia Commons
In 2012, the idea was proposed by Frank Wilczek (Noble Prize winner) of MIT. He suggested a type of matter that exhibits a sort of fundamental oscillation over time even while in a ground state.So, some property of the material goes through a repeating cycle. Wilczek was not the first to use the definition of “Time Crystal” referring to a regular repeating system. In fact, Arthur Winfree firstly proposed it in his “The Geometry of Biological Time” (Winfree A., 2001), where he came up with a simple model in which charged particles in a superconducting ring break what we call “continuous time transnational symmetry”.
That is a fancy way of saying that the system looks different on a global level from one instant to the next. Whereas the regular matter, that is displaying what we call “thermal equilibrium”, only has random internal motion. It is an analogy to the vibrational motion of its comprised atoms in a solid matter [I]. But from one instant to the next, that buzz stays random. In contrast, the intrinsic properties of a regular matter in equilibrium stay the same over time.
A blueprint was created and posted online in August 2016. The author called his paper “The Bridge between the Theoretical Idea and The Experimental Implementation”.
Two teams, one from University of Maryland and one from Harvard, took the basic blueprint of how to make time crystals and both got to work (Yao, 2017). Both teams have used different methods and achieved the same results. The University of Maryland created their time crystals with a line of 10 Ytterbium ions. Within these ions, the spins of their electros were entangled.
The researchers’ goal was to interrupt the ions’ normal equilibrium by using two lasers beams, one to flip the ions and the second to create an electromagnetic field. In fact, the first laser beam induced the ions to flip over and consequently interact with other ions and make them flip over, all within the electromagnetic field produced by the second laser. This process continued until all the ions were oscillating or spinning.
Figure 2. A basic time crystal comprised from a one-dimensional chain of Ytterbium ions made by physicists at the University of Maryland, based on a blueprint derived by UC Berkeley’s Norman Yao. Each ion acts as an electron spin and shows long-range interactions indicated as arrows. (Image courtesy of Chris Monroe)
This behavior was considered common for a normal crystal, but researchers noticed that as the lasers continued to nudge the ions, the ions were reacting more frequently than they were being nudged.
Researchers at Harvard used Nitrogen-vacancy centers, which are certain impurities found in diamonds (Yao, 2017). And instead of using lasers, they used Microwaves to cause the ions in the diamonds to flip and oscillate.
This new form of matter has promising applications in the quantum computing sector and realizing the different forms matter can ultimately take.
- Source: References (1) PBS Space Time channel, Space Time Journal Club, Time Crystals. Retrieved from YouTube.com (2) Properties and States of Matter. Retrieved from quizlet.com [I] (3) Seeker channel, (2017, February, 7), There's A New Form of Matter That Exists in Four Dimensions. Retrieved from YouTube.com (4) Winfree, A. T. (2001). The geometry of biological time (Vol. 12). Springer Science & Business Media. (5) Yao, N. Y., Potter, A. C., Potirniche, I. D., & Vishwanath, A. (2017). Discrete time crystals: rigidity, criticality, and realizations. Physical Review Letters, 118(3), 03040
- Tags: freethinking, fthinking, science, time crystals