Method of reconfiguring particles in a grid of particle traps

A method of reconfiguring particles in a grid of particle traps from an initial configuration to a target configuration, the grid of particle traps having target particle traps and surplus particle traps, the particles being movable along rows of the grid, or along columns of the grid, the rows being transversal to the columns, the method comprising:

• loading an initial configuration of the particles into the particle traps, wherein in said initial configuration, the particles are distributed amongst some of the particle traps;
• measuring the initial configuration, including measuring an absence or presence of the particles in corresponding ones of the particle traps, the initial configuration including a donor column having more particles than target particle traps, and a receiver column having less particles than target particle traps, the donor column being separated from the receiver column by at least one intervening column;
• at the donor column, filling all of the target particle traps including moving some of the particles from the surplus particle traps to the target particle traps, with a surplus particle remaining in the surplus particle traps subsequently to said moving;
• moving said surplus particle to the receiver column along a corresponding one of said rows via the at least one intervening column;
• and
• at the receiver column, filling all of the target particle traps including moving some of the particles, including said at least one surplus particle, from the surplus particle traps to the target particle traps.