Techniques for tuning magnetic potential using a variable gap in a parallel dipole line (PDL) trap are provided. In one aspect, a PDL trap is provided. The PDL trap includes: a pair of dipole line magnets separated from one another by a variable gap g; and a diamagnetic object levitating above the dipole line magnets. The dipole line magnets can be separated from one another by at least one spacer, or a variable gap fixture can be used in which the dipole line magnets are affixed to separate mounts for varying the gap g between the dipole line magnets. A bigger trap or track can be built with multiple segments of PDL trap. A method of operating a PDL trap is also provided.