By Steffen Glaser
This app is only available on the App Store for iOS devices.
SpinDrops provides a novel approach to understand basic and advanced magnetic resonance experiments and the underlying spin dynamics. The app enables users to learn and to become familiar with fundamental concepts of modern NMR spectroscopy in a systematic or playful way. The simple graphical interaction and the immediate feedback to changes of experimental parameters help develop an analytical understanding as well as a well-founded intuition of the mode of action and the design of pulse sequences. The rich dynamics of up to three coupled spins can be explored interactively. The app uses the DROPS representation to depict arbitrary spin states in an intuitive and compact way. The representation is a generalization of the Bloch vector picture and provides a natural, one-to-one mapping between spin states and so-called „droplets“.
• Customizable spin system.
• Up to three coupled spins.
• Characteristic initial states can be chosen from predefined lists.
• Arbitrary initial states can be constructed with the help of a versatile operator editor.
• Real-time simulations of spin dynamics based on the product operator formalism.
• During a simulation, all product operator terms can be listed.
• The new DROPS approach maps quantum mechanical operators to three-dimensional shapes based on spherical harmonics.
• The quantum-mechanical, non-classical behavior of coupled spins can be visualized.
• Abstract concepts such as anti-phase coherence, multiple-quantum order and coherence transfer are visualized.
• Pulse sequences can be selected from a pre-installed list of characteristic homonuclear and heteronuclear experiments, including individual 90° and 180° pulses, Hahn echoes, INEPT, DEPT, selective isotropic mixing, excitation of three-spin order and of multiple quantum coherence.
• A versatile pulse sequence editor makes it possible to efficiently edit the pre-installed standard pulse sequences or to construct new pulse sequences from scratch.
• The pulse-sequence simulation can be interactively scanned, slowed down, accelerated and zoomed.
• The three-dimensional droplets representing individual spins and product operators can be interactively rotated and zoomed.
• Extensive help files are provided, including detailed tutorials, examples, challenges and information on the mathematical background of the DROPS visualization.
• Tutorials show how to define a desired initial state, how to create a new pulse sequence, and how to control the simulation and the graphical DROPS display. Furthermore, the favorable properties of the DROPS visualization are explained and the interpretation of characteristic droplets is discussed. The characteristic shapes representing Cartesian product operators are discussed and it is shown how the coherence order of an operator is reflected in the shape and color of the corresponding droplet.
• Examples and challenges illustrate the interpretation of droplets, their symmetry properties, the evolution of single and coupled spins, the refocussing of offsets and couplings, spectral editing and coherence transfer.
Atomic nuclei and electrons behave in some respects like spinning tops. Nuclear and electronic spins form the basis of advanced quantum technologies, ranging from magnetic resonance imaging (MRI), nuclear magnetic resonance spectroscopy (NMR) and electron spin resonance (ESR) to quantum computing.
What's New in Version 1.2.2
The added display option „Parallax“ allows you to interactively change the perspective by tilting your device, which provides a more intuitive depth perception.