Possible Clues:

• Dreadful feeling's a permanent memory for physicist
• Memory's a big worry at first for physicist
• Measure feeling of dread associated with memory that cannot be erased
• Worker outside gets empty storage space for Swedish scientist
• Physicist showing anxiety with short memory
• Short distance named after a Swedish physicist
• Microscopic unit of length
• Dread memory becoming this short
• Unit of measurement used for the wavelength of light
• Small length unit