国内英语资讯:Chinese scientists make new breakthrough in quantum communication
<p><span word="HEFEI">HEFEI</span>, <span word="July">July</span> 25-- <span word="Chinese">Chinese</span> <span word="scientists">scientists</span> <span word="have">have</span> <span word="made">made</span> <span word="another">another</span> <span word="breakthrough">breakthrough</span> <span word="in">in</span> <span word="quantum">quantum</span> <span word="communication">communication</span>, <span word="demonstrating">demonstrating</span> <span word="long">long</span>-<span word="distance">distance</span> <span word="free">free</span>-<span word="space">space</span> <span word="quantum">quantum</span> <span word="key">key</span> <span word="distribution">distribution</span> <span word="during">during</span> <span word="daylight">daylight</span>.</p><p><span word="In">In</span> <span word="the">the</span> <span word="past">past</span>, <span word="long">long</span>-<span word="distance">distance</span> <span word="free">free</span>-<span word="space">space</span> <span word="quantum">quantum</span> <span word="communication">communication</span> <span word="experiments">experiments</span> <span word="could">could</span> <span word="only">only</span> <span word="be">be</span> <span word="performed">performed</span> <span word="at">at</span> <span word="night">night</span>, <span word="because">because</span> <span word="sunlight">sunlight</span>, <span word="or">or</span> <span word="sunlight">sunlight</span> <span word="noise">noise</span>, <span word="prohibits">prohibits</span> <span word="quantum">quantum</span> <span word="communication">communication</span> <span word="in">in</span> <span word="transmission">transmission</span> <span word="under">under</span> <span word="conditions">conditions</span> <span word="of">of</span> <span word="high">high</span> <span word="channel">channel</span> <span word="loss">loss</span> <span word="over">over</span> <span word="long">long</span> <span word="distances">distances</span>.</p><p><span word="Therefore">Therefore</span>, <span word="the">the</span> <span word="world">world</span>'<span word="s">s</span> <span word="first">first</span> <span word="quantum">quantum</span> <span word="satellite">satellite</span>, <span word="Quantum">Quantum</span> <span word="Experiments">Experiments</span> <span word="at">at</span> <span word="Space">Space</span> <span word="Scale">Scale</span> (<span word="QUESS">QUESS</span>) <span word="launched">launched</span> <span word="by">by</span> <span word="China">China</span> <span word="in">in</span> 2016, <span word="can">can</span> <span word="only">only</span> <span word="send">send</span> <span word="photons">photons</span> <span word="at">at</span> <span word="night">night</span>, <span word="and">and</span> <span word="it">it</span> <span word="takes">takes</span> <span word="at">at</span> <span word="least">least</span> <span word="three">three</span> <span word="days">days</span> <span word="for">for</span> <span word="QUESS">QUESS</span> <span word="to">to</span> <span word="cover">cover</span> <span word="all">all</span> <span word="ground">ground</span> <span word="stations">stations</span> <span word="around">around</span> <span word="the">the</span> <span word="Earth">Earth</span>.</p><p><span word="A">A</span> <span word="team">team</span> <span word="from">from</span> <span word="the">the</span> <span word="University">University</span> <span word="of">of</span> <span word="Science">Science</span> <span word="and">and</span> <span word="Technology">Technology</span> <span word="of">of</span> <span word="China">China</span> <span word="led">led</span> <span word="by">by</span> <span word="Pan">Pan</span> <span word="Jianwei">Jianwei</span>, <span word="an">an</span> <span word="academician">academician</span> <span word="with">with</span> <span word="the">the</span> <span word="Chinese">Chinese</span> <span word="Academy">Academy</span> <span word="of">of</span> <span word="Sciences">Sciences</span>, <span word="has">has</span> <span word="overcome">overcome</span> <span word="the">the</span> <span word="sunlight">sunlight</span> <span word="noise">noise</span> <span word="issue">issue</span> <span word="and">and</span> <span word="demonstrated">demonstrated</span> <span word="free">free</span>-<span word="space">space</span> <span word="quantum">quantum</span> <span word="key">key</span> <span word="distribution">distribution</span> <span word="over">over</span> 53 <span word="km">km</span> <span word="during">during</span> <span word="the">the</span> <span word="day">day</span>.</p><p><span word="Pan">Pan</span>'<span word="s">s</span> <span word="team">team</span> <span word="chose">chose</span> <span word="a">a</span> <span word="wavelength">wavelength</span> <span word="of">of</span> 1,550 <span word="nanometers">nanometers</span> <span word="and">and</span> <span word="developed">developed</span> <span word="free">free</span>-<span word="space">space</span> <span word="single">single</span>-<span word="mode">mode</span> <span word="fibre">fibre</span>-<span word="coupling">coupling</span> <span word="technology">technology</span> <span word="and">and</span> <span word="ultra">ultra</span>-<span word="low">low</span>-<span word="noise">noise</span> <span word="upconversion">upconversion</span> <span word="single">single</span>-<span word="photon">photon</span> <span word="detectors">detectors</span> <span word="to">to</span> <span word="achieve">achieve</span> <span word="the">the</span> <span word="daytime">daytime</span> <span word="distribution">distribution</span>.</p><p><span word="The">The</span> <span word="new">new</span> <span word="technology">technology</span> <span word="was">was</span> <span word="announced">announced</span> <span word="on">on</span> <span word="Monday">Monday</span> <span word="in">in</span> <span word="the">the</span> <span word="journal">journal</span> <span word="of">of</span> <span word="Nature">Nature</span> <span word="Photonics">Photonics</span>.</p><p>"<span word="Our">Our</span> <span word="experiment">experiment</span> <span word="has">has</span> <span word="proved">proved</span> <span word="the">the</span> <span word="feasibility">feasibility</span> <span word="of">of</span> <span word="satellite">satellite</span>-<span word="based">based</span> <span word="quantum">quantum</span> <span word="in">in</span> <span word="daylight">daylight</span>, <span word="and">and</span> <span word="laid">laid</span> <span word="a">a</span> <span word="foundation">foundation</span> <span word="for">for</span> <span word="a">a</span> <span word="satellite">satellite</span>-<span word="constellation">constellation</span>-<span word="based">based</span> <span word="global">global</span> <span word="quantum">quantum</span> <span word="network">network</span>," <span word="said">said</span> <span word="Pan">Pan</span>.</p><p><span word="Quantum">Quantum</span> <span word="communication">communication</span> <span word="is">is</span> <span word="ultra">ultra</span>-<span word="secure">secure</span> <span word="as">as</span> <span word="a">a</span> <span word="quantum">quantum</span> <span word="photon">photon</span> <span word="can">can</span> <span word="neither">neither</span> <span word="be">be</span> <span word="separated">separated</span> <span word="nor">nor</span> <span word="duplicated">duplicated</span>. <span word="Accordingly">Accordingly</span>, <span word="it">it</span> <span word="is">is</span> <span word="impossible">impossible</span> <span word="to">to</span> <span word="wiretap">wiretap</span>, <span word="intercept">intercept</span> <span word="or">or</span> <span word="crack">crack</span> <span word="information">information</span> <span word="it">it</span> <span word="transmits">transmits</span>.</p>
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