The original note, as written at the time
STORAGE FOR PHYSICAL ITEMS (DISGUISER). This device is able to store all the physical items a person owns in a small space about the size of a smartphone. The rules are: the device reconfigures the stored items at a quantum level to occupy a small space and also be retrieved accordingly. However, in doing this it consumes a lot of energy during the storing process, the storage period and the retrieval process. Mass and energy are conserved.
Ongoing development
A device that stores every physical object a person owns in a space the size of a smartphone.
The rules, as stated: it reconfigures the stored items at a quantum level to occupy a small space and retrieves them accordingly — and in doing so it consumes a great deal of energy, during storing, during the storage period, and during retrieval. Mass and energy are conserved.
I want to take the honesty of that last line seriously, because it is what separates this from a magic trick. Nothing here is free. If you compress matter, you pay to compress it, you pay to keep it compressed and you pay to bring it back. A bicycle is not going to sit in your pocket for nothing.
Which means the economics decide the use. A device that costs a great deal of energy per hour cannot be a wardrobe. It can only be a device for things you need rarely, or things whose retrieval is an emergency, or things that must not be found.
That is where the idea stops being a fantasy about tidiness and becomes interesting. What would you keep in a place nobody can search, at a running cost you can barely afford? Documents. Tools for a trade you are not supposed to practise. Your grandfather’s things, if your house might be taken.
The conservation law also has a sharper consequence that the note does not mention: if mass is conserved and the object is smaller than the object, then the device is heavier than it looks, and the weight is the honest part. You would carry your possessions in your pocket and know exactly what they weighed.
I do not think this will exist. I think the sketch is worth keeping because it asks the right question: what would you pay, continuously, to have a thing with you and unavailable to anyone else.