Is this news article about quantum radar legit? [duplicate]











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  • Quantum entanglement as practical method of superluminal communication

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From https://www.digitaltrends.com/cool-tech/quantum-radar-stealth-aircraft/




In principle, a quantum radar functions like a regular radar — only
that instead of sending out a single beam of electromagnetic energy,
it uses two split streams of entangled photons. Only one of these
beams is sent out, but due to a quirk of quantum physics both streams
will display the same changes, despite being potentially miles apart.
As a result, by looking at the stream which remains back home it’s
possible to work out what has happened to the other beam.




Wouldn't this imply faster-than-light information transfer? Is there any way that the interactions of a remote particle can influence a local entangled particle?










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marked as duplicate by AccidentalFourierTransform, Kyle Kanos, Community 2 days ago


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.



















    up vote
    7
    down vote

    favorite













    This question already has an answer here:




    • Quantum entanglement as practical method of superluminal communication

      2 answers




    From https://www.digitaltrends.com/cool-tech/quantum-radar-stealth-aircraft/




    In principle, a quantum radar functions like a regular radar — only
    that instead of sending out a single beam of electromagnetic energy,
    it uses two split streams of entangled photons. Only one of these
    beams is sent out, but due to a quirk of quantum physics both streams
    will display the same changes, despite being potentially miles apart.
    As a result, by looking at the stream which remains back home it’s
    possible to work out what has happened to the other beam.




    Wouldn't this imply faster-than-light information transfer? Is there any way that the interactions of a remote particle can influence a local entangled particle?










    share|cite|improve this question













    marked as duplicate by AccidentalFourierTransform, Kyle Kanos, Community 2 days ago


    This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

















      up vote
      7
      down vote

      favorite









      up vote
      7
      down vote

      favorite












      This question already has an answer here:




      • Quantum entanglement as practical method of superluminal communication

        2 answers




      From https://www.digitaltrends.com/cool-tech/quantum-radar-stealth-aircraft/




      In principle, a quantum radar functions like a regular radar — only
      that instead of sending out a single beam of electromagnetic energy,
      it uses two split streams of entangled photons. Only one of these
      beams is sent out, but due to a quirk of quantum physics both streams
      will display the same changes, despite being potentially miles apart.
      As a result, by looking at the stream which remains back home it’s
      possible to work out what has happened to the other beam.




      Wouldn't this imply faster-than-light information transfer? Is there any way that the interactions of a remote particle can influence a local entangled particle?










      share|cite|improve this question














      This question already has an answer here:




      • Quantum entanglement as practical method of superluminal communication

        2 answers




      From https://www.digitaltrends.com/cool-tech/quantum-radar-stealth-aircraft/




      In principle, a quantum radar functions like a regular radar — only
      that instead of sending out a single beam of electromagnetic energy,
      it uses two split streams of entangled photons. Only one of these
      beams is sent out, but due to a quirk of quantum physics both streams
      will display the same changes, despite being potentially miles apart.
      As a result, by looking at the stream which remains back home it’s
      possible to work out what has happened to the other beam.




      Wouldn't this imply faster-than-light information transfer? Is there any way that the interactions of a remote particle can influence a local entangled particle?





      This question already has an answer here:




      • Quantum entanglement as practical method of superluminal communication

        2 answers








      quantum-mechanics photons quantum-information quantum-entanglement faster-than-light






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      share|cite|improve this question










      asked 2 days ago









      Joel

      193110




      193110




      marked as duplicate by AccidentalFourierTransform, Kyle Kanos, Community 2 days ago


      This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.






      marked as duplicate by AccidentalFourierTransform, Kyle Kanos, Community 2 days ago


      This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
























          2 Answers
          2






          active

          oldest

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          up vote
          17
          down vote



          accepted










          Quantum radar is a real thing. The description is somewhat wrong.



          In radar, you send out a beam of radio waves which get reflected, and you measure them when you come back to look at the objects they were reflected off of.



          In quantum radar you send out a beam of radio waves, which are entangled with another beam. This first beam gets reflected. And when it comes back, you interfere them with the other beam to learn about the objects that reflected them.



          So there's no faster-than-light transfer, because the beam comes back before you extract the information (just like conventional radar).



          There are real theoretical advantages to using quantum radar, but it is also quite a bit more complicated to make it work. The article says that it's not clear whether this is a real device yet or whether it's still vaporware.






          share|cite|improve this answer























          • Where do they keep the 2nd beam while the 1st is our exploring the sky? Does it just keep bouncing around in a bottle somewhere? If the wavelength is kilometers long, wont it dissipate before the 1st gets back?
            – Chloe
            11 hours ago






          • 1




            @Chloe: this is presumably one of the things that makes building these things difficult. For a demonstration system, you could just bounce it off something you made specially for this purpose. For a real, portable, system maybe you could store it in optical fibers. (From wikipedia, it looks like you need to start with visible or near-infrared frequencies to produce the entanglement, after which you convert to microwave frequencies.)
            – Peter Shor
            10 hours ago




















          up vote
          2
          down vote













          Yes. See https://en.wikipedia.org/wiki/Quantum_radar.



          The particles retain their entanglement at large separations.



          This question discusses the issue of whether this implies faster-than-light information transfer:



          Quantum entanglement faster than speed of light?






          share|cite|improve this answer



















          • 2




            Peter Shor’s answer is much better than mine, and I have voted for his.
            – G. Smith
            2 days ago


















          2 Answers
          2






          active

          oldest

          votes








          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          17
          down vote



          accepted










          Quantum radar is a real thing. The description is somewhat wrong.



          In radar, you send out a beam of radio waves which get reflected, and you measure them when you come back to look at the objects they were reflected off of.



          In quantum radar you send out a beam of radio waves, which are entangled with another beam. This first beam gets reflected. And when it comes back, you interfere them with the other beam to learn about the objects that reflected them.



          So there's no faster-than-light transfer, because the beam comes back before you extract the information (just like conventional radar).



          There are real theoretical advantages to using quantum radar, but it is also quite a bit more complicated to make it work. The article says that it's not clear whether this is a real device yet or whether it's still vaporware.






          share|cite|improve this answer























          • Where do they keep the 2nd beam while the 1st is our exploring the sky? Does it just keep bouncing around in a bottle somewhere? If the wavelength is kilometers long, wont it dissipate before the 1st gets back?
            – Chloe
            11 hours ago






          • 1




            @Chloe: this is presumably one of the things that makes building these things difficult. For a demonstration system, you could just bounce it off something you made specially for this purpose. For a real, portable, system maybe you could store it in optical fibers. (From wikipedia, it looks like you need to start with visible or near-infrared frequencies to produce the entanglement, after which you convert to microwave frequencies.)
            – Peter Shor
            10 hours ago

















          up vote
          17
          down vote



          accepted










          Quantum radar is a real thing. The description is somewhat wrong.



          In radar, you send out a beam of radio waves which get reflected, and you measure them when you come back to look at the objects they were reflected off of.



          In quantum radar you send out a beam of radio waves, which are entangled with another beam. This first beam gets reflected. And when it comes back, you interfere them with the other beam to learn about the objects that reflected them.



          So there's no faster-than-light transfer, because the beam comes back before you extract the information (just like conventional radar).



          There are real theoretical advantages to using quantum radar, but it is also quite a bit more complicated to make it work. The article says that it's not clear whether this is a real device yet or whether it's still vaporware.






          share|cite|improve this answer























          • Where do they keep the 2nd beam while the 1st is our exploring the sky? Does it just keep bouncing around in a bottle somewhere? If the wavelength is kilometers long, wont it dissipate before the 1st gets back?
            – Chloe
            11 hours ago






          • 1




            @Chloe: this is presumably one of the things that makes building these things difficult. For a demonstration system, you could just bounce it off something you made specially for this purpose. For a real, portable, system maybe you could store it in optical fibers. (From wikipedia, it looks like you need to start with visible or near-infrared frequencies to produce the entanglement, after which you convert to microwave frequencies.)
            – Peter Shor
            10 hours ago















          up vote
          17
          down vote



          accepted







          up vote
          17
          down vote



          accepted






          Quantum radar is a real thing. The description is somewhat wrong.



          In radar, you send out a beam of radio waves which get reflected, and you measure them when you come back to look at the objects they were reflected off of.



          In quantum radar you send out a beam of radio waves, which are entangled with another beam. This first beam gets reflected. And when it comes back, you interfere them with the other beam to learn about the objects that reflected them.



          So there's no faster-than-light transfer, because the beam comes back before you extract the information (just like conventional radar).



          There are real theoretical advantages to using quantum radar, but it is also quite a bit more complicated to make it work. The article says that it's not clear whether this is a real device yet or whether it's still vaporware.






          share|cite|improve this answer














          Quantum radar is a real thing. The description is somewhat wrong.



          In radar, you send out a beam of radio waves which get reflected, and you measure them when you come back to look at the objects they were reflected off of.



          In quantum radar you send out a beam of radio waves, which are entangled with another beam. This first beam gets reflected. And when it comes back, you interfere them with the other beam to learn about the objects that reflected them.



          So there's no faster-than-light transfer, because the beam comes back before you extract the information (just like conventional radar).



          There are real theoretical advantages to using quantum radar, but it is also quite a bit more complicated to make it work. The article says that it's not clear whether this is a real device yet or whether it's still vaporware.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited 10 hours ago

























          answered 2 days ago









          Peter Shor

          8,7402255




          8,7402255












          • Where do they keep the 2nd beam while the 1st is our exploring the sky? Does it just keep bouncing around in a bottle somewhere? If the wavelength is kilometers long, wont it dissipate before the 1st gets back?
            – Chloe
            11 hours ago






          • 1




            @Chloe: this is presumably one of the things that makes building these things difficult. For a demonstration system, you could just bounce it off something you made specially for this purpose. For a real, portable, system maybe you could store it in optical fibers. (From wikipedia, it looks like you need to start with visible or near-infrared frequencies to produce the entanglement, after which you convert to microwave frequencies.)
            – Peter Shor
            10 hours ago




















          • Where do they keep the 2nd beam while the 1st is our exploring the sky? Does it just keep bouncing around in a bottle somewhere? If the wavelength is kilometers long, wont it dissipate before the 1st gets back?
            – Chloe
            11 hours ago






          • 1




            @Chloe: this is presumably one of the things that makes building these things difficult. For a demonstration system, you could just bounce it off something you made specially for this purpose. For a real, portable, system maybe you could store it in optical fibers. (From wikipedia, it looks like you need to start with visible or near-infrared frequencies to produce the entanglement, after which you convert to microwave frequencies.)
            – Peter Shor
            10 hours ago


















          Where do they keep the 2nd beam while the 1st is our exploring the sky? Does it just keep bouncing around in a bottle somewhere? If the wavelength is kilometers long, wont it dissipate before the 1st gets back?
          – Chloe
          11 hours ago




          Where do they keep the 2nd beam while the 1st is our exploring the sky? Does it just keep bouncing around in a bottle somewhere? If the wavelength is kilometers long, wont it dissipate before the 1st gets back?
          – Chloe
          11 hours ago




          1




          1




          @Chloe: this is presumably one of the things that makes building these things difficult. For a demonstration system, you could just bounce it off something you made specially for this purpose. For a real, portable, system maybe you could store it in optical fibers. (From wikipedia, it looks like you need to start with visible or near-infrared frequencies to produce the entanglement, after which you convert to microwave frequencies.)
          – Peter Shor
          10 hours ago






          @Chloe: this is presumably one of the things that makes building these things difficult. For a demonstration system, you could just bounce it off something you made specially for this purpose. For a real, portable, system maybe you could store it in optical fibers. (From wikipedia, it looks like you need to start with visible or near-infrared frequencies to produce the entanglement, after which you convert to microwave frequencies.)
          – Peter Shor
          10 hours ago












          up vote
          2
          down vote













          Yes. See https://en.wikipedia.org/wiki/Quantum_radar.



          The particles retain their entanglement at large separations.



          This question discusses the issue of whether this implies faster-than-light information transfer:



          Quantum entanglement faster than speed of light?






          share|cite|improve this answer



















          • 2




            Peter Shor’s answer is much better than mine, and I have voted for his.
            – G. Smith
            2 days ago















          up vote
          2
          down vote













          Yes. See https://en.wikipedia.org/wiki/Quantum_radar.



          The particles retain their entanglement at large separations.



          This question discusses the issue of whether this implies faster-than-light information transfer:



          Quantum entanglement faster than speed of light?






          share|cite|improve this answer



















          • 2




            Peter Shor’s answer is much better than mine, and I have voted for his.
            – G. Smith
            2 days ago













          up vote
          2
          down vote










          up vote
          2
          down vote









          Yes. See https://en.wikipedia.org/wiki/Quantum_radar.



          The particles retain their entanglement at large separations.



          This question discusses the issue of whether this implies faster-than-light information transfer:



          Quantum entanglement faster than speed of light?






          share|cite|improve this answer














          Yes. See https://en.wikipedia.org/wiki/Quantum_radar.



          The particles retain their entanglement at large separations.



          This question discusses the issue of whether this implies faster-than-light information transfer:



          Quantum entanglement faster than speed of light?







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited 2 days ago









          AccidentalFourierTransform

          24.5k1366121




          24.5k1366121










          answered 2 days ago









          G. Smith

          2,332310




          2,332310








          • 2




            Peter Shor’s answer is much better than mine, and I have voted for his.
            – G. Smith
            2 days ago














          • 2




            Peter Shor’s answer is much better than mine, and I have voted for his.
            – G. Smith
            2 days ago








          2




          2




          Peter Shor’s answer is much better than mine, and I have voted for his.
          – G. Smith
          2 days ago




          Peter Shor’s answer is much better than mine, and I have voted for his.
          – G. Smith
          2 days ago



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