It is shown that self-focusing of light beams may occur as a result of cooling of a mixture of reacting gases in the case of resonant interaction of light with atoms (or molecules) participating in chemical reactions. Estimates of the duration and degree of cooling are obtained.
Abstract By uncovering the contrast between Artificial Intelligence and Natural-born Intelligence as a computational process, we define closed computing and open computing, and implement open computing within chemical reactions. This involves forming a mixture and invalidation of the computational process and the execution environment, which are logically distinct, and coalescing both to create a system that adjusts fluctuations. We model chemical reactions by considering the computation as the chemical reaction and the execution environment as the degree of aggregation of molecules that interact with the reactive environment. This results in a chemical reaction that progresses while repeatedly clustering and de-clustering, where concentration no longer holds significant meaning.Open computing is segmented into Token computing, which focuses on the individual behavior of chemical molecules, and Type computing, which focuses on normative behavior. Ultimately, both are constructed as an interplay between the two. In this system, Token computing demonstrates self-organizing critical phenomena, while Type computing exhibits quantum logic. Through their interplay, the recruitment of fluctuations is realized, giving rise to interactions between quantum logical subspaces corresponding to quantum coherence across different Hilbert spaces. As a result, spike waves are formed, enabling signal transmission. This occurrence may be termed quantum-like coherence, implying the source of enzymes responsible for controlling spike waves and biochemical rhythms.
This thesis describes two studies with a mixture of ultracold triplet ground state 23Na6Li molecules and 23Na atoms. The first study is to realize the cooling of ultracold NaLi molecules with Na atoms that efficiently exchange kinetic energy when colliding with molecules and bring them to thermal equilibrium with lower temperatures. Such cooling based on inter-particle collisions, which is the so-called collisional cooling, has not been successful in other molecular systems at micro-Kelvin temperatures or below before the work described in this thesis. By harnessing the good-to-bad collision ratio of the NaLi+Na mixture around 200, we increase the phase space density of the molecules by a factor of 20, achieving the temperatures as low as 220 nano-Kelvin. This collisional property arises from the suppression of reactive and inelastic collisions by the polarization of the spin in a chemically non-reactive quartet state, possibly together with the small size and the low mass of the NaLi+Na mixture. The loss rate in the spin-polarized NaLi+Na mixture is more than an order of magnitude lower than the so-called universal rate, which occurs in most molecular collisions as particles are lost or react at short range with unity probability. The second study is about the control of the reactive collisions by magnetically-tunable scattering resonances, so-called Feshbach resonances, between molecules and atoms. By controlling the phase of the scattering wavefunction via a Feshbach resonance at 978 G, we modify the loss rate by more than two orders of magnitude, and such a large dynamic range of tunability in loss is possible only in a molecular system in which the background loss is far below the universal limit, like the spin-polarized NaLi+Na mixture. We explain the observed tunability in loss by a single-channel model based on quantum interference of the scattering wavefunction reflected at long and short ranges, which is analogous to the optical interference in a Fabry-Perot resonator. By fitting our Fabry-Perot model to the precisely measured lineshape of the loss feature at 978 G, we measure short range parameters, such as a background phase shift parameter and a quantum-defect parameter, which indicates that the spin-polarized NaLi+Na has about 4% loss probability at short range. By extending the single-channel model to consider the lifetime of a bound state of a closed channel, we treat a weak Feshbach resonance at 1030 G as a lossy phase shifter. With this extended two-channel model, we measure that the lifetime of a three-body collision complex associated with the resonance at 1030 G is about 60 ns. The work of this thesis shows that the spin-polarization is a simple yet powerful method to suppress reactive collisions in a molecular system and establishes the light triplet molecule as a useful system to study quantum chemistry, molecular scattering resonances, and possibly short range physics.
The creation of a gas of ultracold polar molecules with a high phase space density brings new possibilities beyond experiments with ultracold atomic gases. In particular, long-range, anisotropic, and tunable dipole-dipole interactions open the way for novel quantum gases, with applications including strongly correlated many-body systems, and ultracold chemistry. This thesis will present the final steps to complete control over both internal and external degrees of freedom of the molecule which allows us to control, and even completely suppress, the chemical reactions between molecules. First, the control over internal states has been achieved through coherent state transfer to the ro-vibronic ground state and coherent manipulations of the hyperfine and rotational states with microwave radiation. Second, external degrees of freedom are controlled by loading the gas into an optical lattice. With the molecules loaded into a one-dimensional lattice, the orientation of the molecular collisions is controlled by manipulating both internal (hyperfine states) and external (motional states in the direction of tight confinement) degrees of freedom. Most striking is that by preparing the molecules all in the lowest band of the lattice in the same internal state, the molecular collisions can only occur in a side-by-side" orientation, where the chemical reaction rate is suppressed by the repulsive dipole-dipole interactions. The chemical reaction can be suppressed completely by further constraining the motion in the trap in a strong 3D lattice. Here we see lifetimes longer than 20 s, limited by o-resonant light scattering. Finally, the ac polarizability of the molecules is explored and controlled. The different rotational states of the molecule have different polarizabilities and will experience a different trapping force in both the optical dipole trap or lattice. We show that there is a magic angle" between the quantization axis and the polarization of the trapping laser at which the polarizabilities of two different rotational states can be matched, eliminating dephasing and allowing for coherent manipulations between rotational states.