[HN Gopher] New quantum receiver the first to detect entire radi...
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       New quantum receiver the first to detect entire radio frequency
       spectrum
        
       Author : dnetesn
       Score  : 91 points
       Date   : 2021-02-05 11:41 UTC (1 days ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | secfirstmd wrote:
       | The NSA has just entered the room...
        
       | heterodyning wrote:
       | Fantastic development.
        
       | baxter001 wrote:
       | That opening paragraph is hellishly depressing.
        
         | jacquesm wrote:
         | Once upon a time the people attracting funding for what became
         | the internet were using language just like that. Almost all
         | tech has good and bad applications.
        
         | dchichkov wrote:
         | In that particular case tax money were used on peer-reviewed
         | research. Rather than emitting carbon driving a tank or flying
         | yet another airplane. Not that bad.
        
       | madengr wrote:
       | https://www.rydbergtechnologies.com/
        
       | danvk wrote:
       | Could this be useful for astronomers?
        
       | [deleted]
        
       | JabavuAdams wrote:
       | Does anyone have insight into why this is published in the open
       | literature, if it is such a militarily-exploitable advance?
        
         | blaeks wrote:
         | what if they know/calculate what is implied into
         | development/utilization so they know no one but them (or the
         | same class opponent) could replicate it
        
         | stevehawk wrote:
         | i dont think we have any enemies questioning whether or not we
         | listen to radio frequencies?
        
           | mattkrause wrote:
           | Yup. The cool thing is that it's an all-in-one system. I'm
           | not sure there's a huge strategic advantage in knowing
           | whether someone has one mega-radio or a bunch of separate
           | modules glued together.
           | 
           | Plus, I linked to the preprint above. It's ten pages long--
           | you're not going to be able to build your own based on it;
           | it's more just documentation that the thing exists.
        
       | bob1029 wrote:
       | What sort of exotic signal processing solution would be required
       | to support 20GHz of bandwidth at any useful sampling rate and bit
       | depth? How would you actually collect a meaningful amount of
       | information from every station in range simultaneously?
       | 
       | I feel like this is something that may be possible in physics,
       | but is not well supported in practical applicability. The amount
       | of signal processing hardware required to support this in the
       | field should be a deal breaker with modern hardware, unless there
       | are some really strong constraints regarding the bands &
       | modulation schemes actually being monitored simultaneously.
       | 
       | Assume 40GHz sample rate for bare minimum no aliasing over the
       | 20GHz spectrum, 8 bits per sample. You will wind up with ~320Gbps
       | of data to deal with.
        
         | leeoniya wrote:
         | "hold my beer" -- CERN
         | 
         | https://hackaday.com/2020/05/14/crunching-giant-data-from-th...
        
         | dogma1138 wrote:
         | Ask Keysight
         | 
         | https://www.keysight.com/en/pdx-2935683-pn-UXR0802A/infiniiu...
         | 
         | That said most signal processing scopes at high frequencies are
         | analogue, so you are dealing with Giga Samples / Second not
         | bps. But yes to to make sense of the actual data it would
         | require some serious networking and storage but that might not
         | be necessary for many applications.
        
         | blihp wrote:
         | The main application would seem to be no longer needing to scan
         | the spectrum for activity... you'd continuously be scanning
         | (effectively) all of it simultaneously. A least one useful bit
         | information you'd be obtaining from this is simply _where_ in
         | the spectrum activity is occurring.
        
         | insert_coin wrote:
         | A quantum signal processor of course!
         | 
         | It is however 5-10 years away.
        
       | etaioinshrdlu wrote:
       | It seems like lower radio frequencies require really big
       | antennas. Does this somehow work around that enabling very
       | compact low frequency antennas?
       | 
       | Low frequencies are very useful because they penetrate structures
       | more easily.
        
       | [deleted]
        
       | aj7 wrote:
       | Miniaturization and ruggedization for practical applications will
       | require a lot of work. Not only are the atoms contained in a
       | heated tube, but, unlike atomic clocks, sophisticated tunable
       | laser technology must also be employed. So only very high value
       | missions, like large satellites or ground installations are
       | practicable.
        
         | jacquesm wrote:
         | This is how every tech breakthrough starts. Remember when
         | lasers required high vacuum tubes and high voltage power
         | supplies with ridiculous specs, serious glass making skills and
         | pretty much daily cleaning of all the optics? And now they are
         | just about everywhere and cost pennies.
        
       | notum wrote:
       | Another StarTrek tech entering the reality realm.
       | 
       | When Voyager stumbled upon a industrial-age civilization Kim
       | immediately notified Janeway that he's detecting "Old style" FM
       | broadcasts. I recall thinking "why would a 24th century subspace-
       | communicator equipped star ship even monitor those?"
       | 
       | I got my answer, quantum receivers, they monitor everything.
        
       | mattkrause wrote:
       | Preprint of the paper described in the article:
       | https://arxiv.org/abs/2009.14383
        
       | avsteele wrote:
       | My company can create some of the highest density cold Rydberg
       | (Cs) atom setups in the world. We use our tech for focused ion
       | beams, but I'm interested in this application. Our equipment
       | isn't 'miniature' but everything is in a single 19" rack.
       | 
       | If anyone who is an expert on the RF side wants to drop ideas
       | below or contact me at adam@zerok.com to brainstorm please feel
       | free.
        
       | tyler3991 wrote:
       | Pretty big win for RF. Peak sensitivity -145 dBm/Hz. Little bit
       | of a stretch to say entire RF spectrum, but 0 -> 20 GHz is still
       | really cool.
        
         | Animats wrote:
         | Right. If it went into the terahertz range, it would help open
         | up that area. 5G cell phones go higher than 20GHz than that.
        
           | jacquesm wrote:
           | Even so, this is pretty impressive, not all that long ago
           | this device would be SF and people would doubt it would ever
           | exist.
        
             | Animats wrote:
             | Not that long ago, the radios in a cell phone would be SF.
        
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       (page generated 2021-02-06 23:00 UTC)