Logic Masters Deutschland e.V.

Puzzle link: Play on SudokuPad.

Rules: Cells with a cat contain Schrödinger's cats, i.e., multiple possible options for digits. Preserve their superposition state by not letting them interact too strongly with the environment...

Place single digits 1 through 6 into some, but not all, cells of the grid without repeats in any row, column, or box. In a cage, every cell must contain a single digit, and those digits sum to the total given as a clue in the top left corner. Every cell that has only one option for a single valid digit must be filled with that digit. Every cell with a cat, and possibly others, must allow at least two options for a valid single digit; these options must not be resolvable based on the given rules and the contents of all other cells.

Your feedback, ratings and comments are highly appreciated. Have fun!

Background: This puzzle refers to the physics of Schrödinger's cat. While this is often described as a thought experiment on superposition in quantum mechanics, Schrödinger cat states are generated and observed experimentally, though not with real-live cats. To keep a quantum state in such a superposition, it should not interact too strongly with the environment. This forms the basis of the puzzle in which such an interaction might be brought about by the Sudoku rules that digits must not repeat within a row, column, or box.

Schrödinger cells that can take on several possible digits have been introduced in Sudoku. Here, I wanted to take a different approach emphasizing that interactions with the environment need to be avoided to protect Schrödinger's cats.

Example: The following image provides a fully solved example on a 4x4 grid. You may solve the example for yourself here on SudokuPad.