Progress in making Star Trek tech real

There's been a lot of cool sci-fi technology over the years in Star Trek: transporters, phasers, faster-than-light travel. And by sci-fi I mean 'convenient but impossible stuff that helped get the plot move a long'. Star Trek TOS introduced a number of things, NG a few more, the movies I can't think of anything more than "an excess of chronotron particles has created an anomalous rift in the space-time continuum".


But it's kind of funny - since the original series, engineers have almost taken these sci-fi things as a challenge. "Star Trek can do it in the 23rd century. I will make it happen now!". Some things have actually happened; some have been found to be physically impossible. And all sorts between.
Here is an inventory of these plot devices/technologies and 'our' progress (star date spring 2015, 50 years after TOS). 

• transporter - (from The Guardian). It (presumably) records all the positions and velocities of all particles in an abject, and recreates them ... elsewhere. This is theoretically possible and experimentally shown to work on individual electrons. But it needs a lot of work to scale this up to safely transfer humans. It just seems computationally infeasible and would take inordinate amounts of energy to make sure that all the atomic particles get transferred to just the right place. Some scenarios of this require that you have to kill your own doppelganger (it's really just a duplication device). Also, there are myriad niggling details like accounting for the relative speeds of the source and target locations (planets and satellites spinning around at huge velocities). However, one of the side benefits of transporter technology is that it allows you to remove infectious diseases and compute your genome, which, if the quantum relocation problems are solved, would surely be a piece of cake to do. But might allow mishaps aplenty as in many Startrek subplots, and other movies like The Fly. Not impossible, but very difficult with today's technology and economics. There are claims that transporting of objects has been done (see The Guardian article), but I consider that cheating of a form that just isn't cricket.That's a form of manufacturing (which may suffice for the entry on replicators).

• automatic door opening - https://www.youtube.com/watch?v=6CSmkym-Stw  This is old news. Every grocery store has had these for years. Either through motion sensors, RFID chips, or weight pads

• artificial gravity - this is a difficult one. What does it mean to have this technology? Without a large mass, can you simulate attraction to a flat surface? Or does a spinning cylinder which mimics gravity count (you'll be able to walk mostly normally, but water will still form messy blobs instead of pouring straight down)? The latter gets a lot, but the former...I don't think there is any physics that says this is at all possible. There's no graviton generator.
  
  However, one can cheat reasonably here. You can 'simulate' gravity on a surface as long as you make the surface accelerate towards the thing you want to exhibit gravity against. Make you spaceship accelerate towards a destination at 32 ft/sec/sec and It feels just like Earth! (turn around halfway and slow down at the same rate, because deceleration is just acceleration in the other direction. Note that this requires lots of fuel, fuel the whole way, rather than just coasting.
  
  Or the old fashioned spinning cylinder would work (with a large enough cylinder), going around a circle is acceleration, too.
  
  Neither of these is cheating, those are real equivalents of gravity. But if what you want is localized gravity, say over a square yard, as different from the adjacent square yard, then no, that's not going to happen.
  
  Progress score: by thinking of gravity as acceleration then yes in some contexts. But, arbitrarily, no, physically impossible.

• invisible force fields or shields (for protection in battle) - same thing. This is actual magic. In that science is not involved. OK, this might be cheatable with lots of magnets. Progress score: never

• cloaking device - The ability to make yourself invisible. Or maybe they've rethought what it means into a solvable formation. Yes, there is technological progress on this, wrapping light to go around an object, or camera on one side projecting to the other. Progress score: sometimes totally yes, other times in progress.

• tractor beam - If there were arbitrary artificial gravity, it could be slightly modified to produce a tractor beam. Except I've heard of laser/magnet/ultrasound pincers for very small scale manipulation in air of particles (like dust). Progress score: not at all. Cheating: maybe

• phasor (weapon for stun or kill) - sorta, not really. Like solar energy, there is the basic technology there, but it just hasn't progressed well. There are 'energy beams' but they take a lot of energy to produce, which is probably too difficult to engineer down to a handheld. But what about those green pointer lasers? I guess making you close your eyes is something. Progress score: sort of, very slow

• photon torpedo - I don't know what's inside that thing. But we have had bad enough destructive bombs since before Star Trek came out. Progress score: already done, but maybe it doesn't glow or have flashing lights on it as it approaches its target, probably for good reason.

• faster than light travel - This is obviously theoretically impossible, even for information, forget objects, All that wormhole stuff is nonsense (at least wormholes that allow an entire ship to travel through unscathed). Dude, if you go into a black hole, you'll be ripped apart before you even get to the event horizon. Of course there may be some cheating thing (transporters?) Progress score: never

• computer disks -
  
  
  
  ( from filmjunk) quickly surpassed and obsoleted. I love this one as an example because it was one of the mini minor details in the TV shows that really made it great. Instead of big file folders of paper. "Just a small piece of plastic? Wow, the future is crazee!." That was the 60's. Then with PCs in the late 70's/early eighties, the floppy disk could be used as a replacement for paper. and it slowly got smaller until the early nineties the 3.5 in disk was widely used and pretty much identical in function to the ST disk. By the mid 2000's, we have thumb drives, barely noticeable on your keychain. And now people keep everything in the cloud. We don't even need a physical device to keep our files, it's just there in the ether. ST had the idea, people created it, people surpassed it, no one uses physical devices anymore.

• communicator - Cellphones were invented in the '80s and have improved ever since, even better with apps (smart phones). I guess there are some limitations like we can't talk to the ISS from the ground with our phones (maybe someone at NASA can?) Wait.. we can tweet to the ISS on our phones. Progress score: Done.
• talking computer - yes, to great extent. It's not perfect.It doesn't do all languages automatically. But for European languages, it gets syntax  and word choice mostly right (except for a few dings). Slow but steady progress by scientists over the years have created this (despite the bravado of the earliest years of AI claiming it could be done in a couple of years)
• tricorder (handheld noninvasive medical analysis) - not yet, but getting there. There are all sorts of tools now for blood sugar, blood oxigen, temp, etc. Also, radiology is slowly miniaturizing. Next hurdle, hand held DNA sequencer?
• universal translator - crazy impossible AI in the 60's. Hardwon but infinitesimally incremental progress over the years has recently resulted in a passable intermediate stage by Google. Kind of the same explanation as Siri. It's not the best but it's workable if you don't talk too fast.

• DNA analysis - I mentioned the genome when I discussed the transporter and tricorder. Currently, if you have the locations of all the atoms in your body) presumably one can then go through some process on that data to get your DNA sequenced. But without (which the tech to produce the transporter would allow) genome can be done by a big machine for <$1K, but analysis and miniaturization not yet.
• time travel - OK everybody, just shut up. Time travel is not possible at all. At least not in any way like in popular fiction. Wait, I'm sorry, Planet of the Apes got it perfectly right. You can travel into the future (we're already doing that right now, right?), but faster than normal. That is, if you travel at a non-trivial percentage of the speed of light, your time will be slower than others, and when you come back, everybody will have aged more than you. Other people will think you popped in from the past. That's about the extent that physics allows time travel. That's it. No going back in time (we'd have noticed people doing it already), and if you could you couldn't do anything that hasn't happened already. It's all just a plot device that appeals to successful primate brains. When the rodents take over (look at their hands!) and start telling stories, they'll come up with it too.
• replicator - not really, but minimal progress. I consider 3D printing to be one part of this for which there has been great progress (and still more to go). The 3DP will create the physical substrate for an object (the parenchyma if you will). The missing part is the chemical or substance part. If you want to replicate a ham sandwich, you can (could, with some work) 3DP the shape and consistency of the bread, tomato, lettuce, ham, and mayo. But for each of those you still need the taste. And that will need some chemical engineering that I am not aware of. Subtleties in taste, not everything in the grocery store can be imitated with artificial flavoring. Progress score: early stages of prototyping
• holodek - we're almost there. In the 90's there were rooms called 'The Cave' where your environment was displayed on the walls, and you held onto a control device that noted your orientation and movement. It was neat. On the way but not the best. The gaming community has created very life like images and environments. If you call it virtual reality there are VR helmets now. Not totally VR, not total immersion, but even closer. Basically what is needed is better plots and virtual acting.

Did I forget some glaring ones? Sure, the communicator. We've done it. Next.

And surely there are a lot of technologies mentioned before and after, not in ST, that are worthy of discussion. But this is about ST.

For many of these, where I say no or impossible, I'm pretty much challenging you to go around it, by rethinking the rules or outright cheating. That's how engineering works. To get from A to B better than a horse or bird is not to add more legs or implement wings. So maybe you can make a levitating car (but why?) as long as you have a track or ferromagnetic surface.