Quantcast
issue
Read articles, including Science News stories written for ages 9-14, on the SNK website.
Blog: Heisenberg’s uncertainty principle still certain
Despite rumors to the contrary, a mainstay of quantum physics is just as (un)certain as ever.
A+ A- Text Size

Despite rumors to the contrary, a mainstay of quantum physics is just as (un)certain as ever.

By Laura Sanders

Web edition: August 5, 2010

At first glance, a Nature Physics paper published online July 25 may have appeared to threaten the Heisenberg uncertainty principle, which says that in the quantum world of electrons, photons and other tiny particles it’s impossible to know certain pairs of physical properties, such as a particle’s position and the momentum, at the same time.

The paper reports that in certain quantum scenarios, it’s possible to have a device that stores knowledge of the exact position and exact momentum of a particle. But try to stifle your panicky screams for just a little bit longer. After a reasonable amount of scrutiny (and a few quick checks with study coauthor Roger Colbeck at the Perimeter Institute for Theoretical Physics in Canada), I found out that the result won’t have Heisenberg rolling over in his grave anytime soon.

“It is not the case that Heisenberg has been overturned,” Colbeck says.

Whew.

Rather, the paper points out that in certain extreme quantum scenarios, the uncertainty principle may not apply in its original form.

In the new paper, Colbeck and his colleagues examine what would happen mathematically if an electron is quantumly linked with a perfect quantum memory, a device that can receive and store all the vast quantum information about a particle. (Such systems, including this one that Alexandra Witze recently wrote about, have been created, but can’t yet store the quantum info long enough to be useful.)

Colbeck and his colleagues studied what would happen if the quantum memory and the particle were entangled, that is, held in a linked existence such that what happens to one seems to instantaneously affect the fate of the other.

An entangled quantum memory could hold information about a particle that could be measured to reveal the particle’s position perfectly, and information that could be measured to reveal the momentum perfectly. “So we can have a memory which stores both the position and the momentum,” Colbeck says.

Uh-oh.

If we stopped here, Heisenberg might get a little shifty down there. But there’s a caveat, and it’s a big one: “Although the memory stores both the position and the momentum, we can only read out one of the two,” Colbeck says.

As physicists attempt to read out one of these properties exactly, the other gets more and more mysterious, just as Heisenberg thought. So for now, Heisenberg can rest easy, because this uncertainty is still certain. 

For more details, check out one of the paper author’s blog posts about the result here.

Comment
Print Friendly and PDF

M. Berta et al. The uncertainty principle in the presence of quantum memory. Nature Physics. Published online July 25, 2010.
Dio:10.1038/nphys1734
[Go to]


Further reading: A. Witze. Memories made of light. Science News. Vol. 178, July 17, 2010, p. 16.
[Go to]

author’s blog
[Go to]

Comments (17)

Please alert Science News to any inappropriate posts by clicking the REPORT SPAM link within the post. Comments will be reviewed before posting.

  • And cannot we read the position from particle and momentum from quantum memory? What if we build multiple quantum memories linked to single particle? Cannot we watch the momentum in one memory and position in another one?
    Matej Spanik Matej Spanik
    Aug. 6, 2010 at 5:18am
  • Quantum entangled pairs for the experiment is not the same.
    When particles are entangled, their very nature is no longer natural.
    In the same sense that casting light onto the experiment causes the electrons to shift, thereby ruining the experiment, quantum entangled pairs will not do.
    Hans Moleman Hans Moleman
    Aug. 6, 2010 at 11:36am
  • It would seem that were you present at the moment of creation you could know both.
    Stanley Kerns Stanley Kerns
    Aug. 6, 2010 at 5:27pm
  • There is no such existence as UN-ENTANGLED.

    The very nature of reality requires entanglement.....in fact there no existence that is not a form of interference.....

    Holograms point to the truth of this.

    The fact that time only "appears" to go in one direction is a kind of a proof....

    There is such a thing as time travel, and it is possible by adjusting the entanglement of the current existence....touching the past and altering it, alters the future....


    but you knew that right?


    There are some past events that are relatively pure in their current form.

    .

    .

    .
    A. MONster A. MONster
    Aug. 8, 2010 at 10:30am
  • Things have a degree of probability of existing, and are constantly forming and not-forming.

    Since the Universe is affected by the whole of existence(s) the actual effector my be non-local...

    but you knew that right?


    Of course working in "isolation" at near absolute zero may minimize the interactions

    one can't avoid them

    can one.

    .

    .

    .
    A. MONster A. MONster
    Aug. 8, 2010 at 10:36am
  • If one knew how, one could visit a site and move the present state of things to prevent a future state....

    .

    doncha know.
    A. MONster A. MONster
    Aug. 8, 2010 at 10:39am
  • Its true that,Quantum entangled pairs for the experiment is not the said.
    When particles are entangled, their very nature is no individual innate.
    In the synoptic sentience that cast morality onto the experimentation causes the electrons to dislodge, thereby devastation the enquiry, quantum entangled pairs will not do.
    An entangled quantum retentiveness could interruption information nigh a particle that could be plumbed to divulge the particle's orientation utterly, and substance that could be metrical to display the force dead.
    -------------
    Travel Help


    krish krish
    Aug. 16, 2010 at 7:41am
  • entangled photons can become unentangled and vice-versa. aligned reinforced cooperative field flows exist and are fundamentally different then interference patterns. absolute zero is not isolation in fact like all laws it is meant to be broken as evidence by the varying fine-structure constant and varying uncertainty principle. probabilities are after the fact past observations that show your ignorance like why the sun will shine tomorrow. mathematics relies on constants that vary over space and time, and life may have 3 beings instead of 2 beings making divorce and child support more complicated.
    quanta universe.com quanta universe.com
    Oct. 17, 2010 at 10:43am
  • - Hallelujah !! String Theory !!
    ==.
    Science has always been a source of heresy.
    ====.
    Lee Smolin wrote:
    I have written this book in the hope that it will contribute
    to an honest and useful discussion among experts and
    lay readers alike.
    / ‘ The trouble with Physics’. Page XVIII. /
    I will take Smolin’s proposition and try to explain my
    amateur’s thoughts about that was called ‘String theory’.
    =============.
    #
    Three years ago I posted an article ‘ The Special Theory
    of Relativity’ I wrote:
    ‘ String theory acts in 11- D space.
    But if we don't know what 1+1 = 2 is
    how can we know what 5+4 = 9 is?
    And if we don't know what 4-D negative Mincowski space
    is how can we understand 11-D space ( String theory) ?’
    I wrote: . . . .
    ‘If I were a king, I would publish a law:
    every physicist who takes part in the creation
    of 4D space and higher is to be awarded a medal
    "To the winner over common sense".
    Why?
    Because they have won us using the
    absurd ideas of Minkowski and Kaluza. ‘
    This was a reason that I refused to read any information
    about ‘String theory’.
    And later on different forums I posted emails, trying
    to explain, that the point is only a shadow of real particle,
    that it is impossible to understand Physics and Nature
    thinking of particle as a point.
    I wrote: In 1915 Einstein connected Mass with Geometry.
    Maybe now, in 2010, somebody will try to understand the
    interaction between an elementary particle and geometry.
    I wrote:
    If physicists think about a particle as a " mathematical point"
    the result can be only paradoxical. And I am sure if somebody
    takes into consideration the geometrical form of particle
    the paradoxes in Physics will disappear.
    #
    Travelling in Scotland, by chance, in a secondhand shop
    I bought a book: ‘ The trouble with Physics’ by Lee Smolin.
    This book changed my opinion about ‘String theory’.
    Now I say: Hallelujah ! Hallelujah ! Why? Because
    ‘… particles could not be seen as points, which is how
    they always been seen before. Instead, they were ‘stringlike’,
    existing only in a single dimension, and could be stretched, . .
    And . . . they vibrated.’ / Page 103. / ‘ . . the idea of particles
    as vibrations of strings was the missing link that could work
    powerfully to resolve many open problems.’ / Page 124./
    It is nice. It is pleasant to read this idea.
    So, the string particle is a dynamic particle. And the string can
    have different geometric forms: ‘String can be both closed and
    open. A closed string is a loop. An open string is a line;
    it has ends’. / Page 106./ And now few physicists try to connect
    forces, movement and geometry of the quantum particle together.
    Hallelujah ! It is a progress. It is a step to truth.
    Now I say: the truth is hidden in the ‘ String theory ’.
    #
    But there are many string theories. And the growing catalogue
    of string theories evokes trouble. Because one theory is better
    than the other one, but at the same time each new theory brings
    new problems. Maybe therefore Lee Smolin wrote:
    ‘ . . . at least one big idea is missing.
    How do we find that missing idea?’ / Page 308. /
    Interesting: What was missed by ‘ the brightest and
    best- educated scientists’ who worked very hard doing
    many complicated calculations ?
    New particle? New D ? New force? New idea?
    Where did they have an error?
    I will try to understand this situation.
    #
    If I were professor I would great super – super 55D for
    explaining everything. But I am a peasant and the best way
    for me is to take the simplest reference frame – the Euclidean
    space ( 2D) . And maybe (who knows ?) Newton was right
    saying: ‘ Truth is ever to be found in simplicity,
    and not in the multiplicity and confusion of things.’
    Now I will put a virtual- ideal particle in this 2D.
    The 2D is a thin and flat homogeneous space, so my particle
    also must be thin and flat and very symmetrical.
    Can it be a very thin and tiny limited line- string?
    No. In my opinion even this very thin and tiny line
    under good microscope will be looked as a rectangle.
    Can it be a very thin and tiny limited loop?
    No. The geometrical form of a loop is too complex,
    needs supplementary forces to create it.
    Can it be a very thin and tiny limited circle?
    Yes.
    From all geometrical forms the circle is the most symmetrical.
    The surface of a circle takes up the minimal area it can and
    I will write it by formula: C/D= pi= 3.14. (!)
    But I can put many particles there, for example,
    Avogadro’s number of particles: N(a). (!)
    #
    What is my next step?
    If I were a physicist I would say that 2D must have some
    physical parameters like: volume (V), temperature (T)
    and density (P). Yes, it seems the idea is right.
    Then, volume (V) is zero,
    temperature (T) is zero
    but . . but density (P) cannot be zero if 2D is a real space
    then its density can approximately be zero.
    #
    What can I do with these three parameters?
    I have only one possibility, to write the simplest formula:
    VP/T=R (Clapeyron formula !)
    What is R? R is some kind of physical state of my 2D.
    And if I divide the whole space R by Avogadro’s
    numbers of particles then I have a formula R/ N(a) = k,
    then k ( as a Boltzmann constant) is some kind of
    physical state of one single virtual- ideal particle. (!)
    #
    But all creators of Quantum theory said that this space,
    as a whole, must have some kind of background energy (E).
    And its value must be enormous.
    But the background mass of every Avogadro’s particles
    in 2D has approximately zero mass, it is approximately
    massless (M).
    So, if I divide enormous energy (E) by approximately
    massless (M) then the potential energy/ mass of every single
    virtual- ideal particle ( according Einstein and Dirac) is
    E/M=c^2 (potential energy/mass E/M=c^2 ! )
    ( I don’t know why physicists call E/M= c^2 ‘rest mass’
    and never say potential energy/mass E/M=c^2 .)
    In potential state my particle doesn’t move,
    so its impulse is h = 0.
    #
    My conclusion.
    I have virtual- ideal- massless particle which has
    geometrical and physical parameters:
    C/D= pi= 3.14 . . . . , R/ N(a) = k, E/M=c^2, h=0.
    All my virtual- ideal- massless particles are possible to call
    ‘ bosons’ or ‘antiparticles’ . These bosons are approximately
    massless but have huge potential energy/mass E/M=c^2 .
    But I have no fermions, no electric charge, no tachyons,
    no time, no mass, no movement at this picture.
    #
    Smolin wrote: ‘ – the missing element – must have been
    one of the earliest triumphs of abstract thinking.’/page 102/
    Where was ‘the earliest triumphs of abstract thinking.’?
    In the hope to understand Smolin’s thought I will draw
    historical scheme: Quantum Theory ---->
    ----> Thermodynamics ----> Theory of gases ----> Ideal Gas.
    So, ‘the earliest triumphs of abstract thinking.’ was connected
    with idea of an ‘Ideal Gas’. From Ideal Gas our trouble with
    physics begins. I think the ‘Ideal Gas’ cannot be an abstract
    hypothesis. In my opinion the ‘Ideal Gas’ must be a real model
    of vacuum: T=0K . We can use all laws of ‘Ideal Gas’ for
    explaining the situation in Vacuum: T=0K. The ‘ Ideal Gas’ as
    abstract as ‘ Vacuum ‘ and vice versa.
    ===================..
    Now, thinking logically, I must explain all the effects of
    motions. And. . . and I cannot say it better than Newton:
    ‘For the basic problem of philosophy seems to be to discover
    the forces of nature from the phenomena of motions
    and then to demonstrate the other phenomena from these forces.’
    #
    How can one single virtual- ideal particle start its movement?
    At first, it will be right to think about some simple kind of
    movement, for example: my particle will move in straight line
    along 2D surface from some point A to the point B.
    What is possible to say now?
    According to the Michelson-Morley experiment my particle
    must move with constant speed: c=1 and its speed is independent.
    Its speed doesn’t depend on any other object or subject, it means
    the reason of its speed is hidden in itself, it is its inner impulse.
    This impulse doesn’t come from any formulas or equations.
    And when Planck introduced this inner impulse(h) to physicists,
    he took it from heaven, from ceiling. Sorry. Sorry.
    I must write: Planck introduced this inner impulse (h) intuitively.
    I must write: Planck introduced his unit (h) phenomenologically.
    At any way, having Planck’s inner impulse (unit h=1) my
    particle flies with speed c=1. We call it photon now.
    Photon’s movement from some point A to the point B
    doesn’t change the flat and homogeneous 2D surface.
    Of course, my photon must be careful, because in some local
    place some sun’s gravitation can catch and change its trajectory
    I hope it will be lucky to escape from the sun’s gravity love.
    #
    My photon can have other possibility to move. This second
    possibility was discover by Goudsmit and Uhlenbeck
    in 1925. They said the elementary particle can rotate
    around its diameter using its own angular inner impulse:
    h * = h /2pi. So, when photon rotates around its diameter
    it looks like a string ( open string) and this string vibrates.
    My god, that is a strange technical terminology the physicists
    use: ‘ vibrate, vibration’.
    If I were a physicist I would say no ‘ vibrate, vibration’ but
    ‘ frequency’, ‘the particle rotates with high frequency’.
    The frequency is a key to every particle, by frequency we know
    the radiation spectrum of various kinds of waves.
    Now I can say: then my photon starts to curl its rotation
    goes with enormous frequency, faster than constant speed
    of photon. Now its speed is c>1. We call it ‘tachyon’.
    The tachyon’s spinning creates electric charge and
    electrical waves and now we call it ‘electron’ or ‘fermions’.
    So, in my opinion, virtual- ideal particle, photon, tachyon
    and electron are only different names of one and the same
    particle – quantum of light.
    The frequency of every string particle can change.
    ( The various states of vibration . . . Page 103.)
    The geometrical form of string can change.
    ( When they gained energy, they stretched; when they
    gave up energy, they contracted - Page 103.)
    Thanks to rotating movement the ‘massless’ of particles
    increased and it became real observed particle.
    Stop ! !!
    I have missed here something important.
    What have I missed?
    #
    ( When they gained energy, they stretched; when they
    gave up energy, they contracted - Page 103.)
    What does it mean? What did Smolin want to say?
    How can I understand this process ?
    . . . . . . . . . . .
    My particle is a circle. When this circle started to curl around
    itself its form changed. Now it has volume and looks like a sphere.
    What is the law between particle’s volume and energy?
    I think: big volume – low energy, small volume – high energy.
    The more speed / impulse ----> the more particle (as a volume)
    compress ----> the more energy .
    And when the speed decrease – - the energy decrease too –
    but the volume of particle will increase.
    My particle behaves like ‘ a springy circle’ (!)
    This springy circle can curl into small sphere which must
    have volume and therefore can be describe as a
    ‘stringlike particle with vibrations’ only approximately .
    Springy particle - it means the particle is able to spring back
    into its former position. In my opinion this is the meaning of
    ‘ The Law of mass/energy conservation and transformation’
    #
    Once more.
    Quantum of light has potential energy (- E=Mc^2 ).
    When it starts to curl around its diameter the potential energy
    (- E=Mc^2 ) is hidden and we can observe its electronic
    energy ( E=h*f).
    But there is situation when this hidden potential energy goes
    out and we can see its great active power ( + E=Mc^2 )
    looking the destroyed cities of Hiroshima and Nagasaki.
    In my opinion the particle’s transformation from one state into
    the other was legalized as ‘ The Law of mass/energy
    conservation and transformation’.
    #
    Different geometrical forms of string particle
    ( open - closed ), different frequencies of string particle are
    reason of different radiation (from ultraviolet to infrared ),
    are also reason of new situation in 2D.
    Now the surface of my 2D in local area is changed.
    On one hand it is electromagnetic field now,
    on the other hand the spinning electron
    changed the temperature of the surface in local area.
    Now this local area has Debye temperature: Q(d)= h*f(max) / k.
    Maybe in this space a grain of gravity theory is hidden.
    Who knows?
    ==================..
    My conclusion.
    It is no bad idea to ask question:
    what are physical parameters of your new super D?
    It is possible to understand many things using 2D.
    The missing ‘big idea’ in ‘String theory’ is hidden in the
    simple question: ‘ What was the form of particle before
    it started to curl?’
    The time appears as a period of electron’s action.
    I ‘mix bosons with fermions’ (page 105) without using
    any supersymmetries.
    And I have:
    a) In potential state the impulse of particle is h = 0. ( boson)
    b) Having Planck’s inner impulse (unit h=1) my
    particle moves straight with constant speed c=1. ( photon)
    c) Having Goudsmit / Uhlenbeck inner angular impulse
    h * = h /2pi. the particle rotates around its diameter.
    ( electron/ tachyon/ fermion).
    Maybe the different conditions of (h) is the key to all
    other phenomena.
    Maybe this process can explain ‘the dualism of particle.’
    Maybe this interpretation can explain where the energy comes from.
    Maybe, if the space of my circle curls and changes then we need to
    use Riemann geometry .
    Maybe, if the speed of the particle is independent and self-contained
    then we need to use nonlinear equations.
    Maybe . . . . .
    Maybe it is time to end now.
    I reread my article. It is not bad, not bad for amateur,
    who thinks about philosophy of physics for 28 years.
    Of course, my interpretation is only scheme. And if
    I were a physicist I would make from this scheme a theory:
    ‘ Elementary particle as a springy circle’.
    But as a peasant I can only hope that maybe somebody
    from Smolin’s ‘few . . . most talented and accomplished
    physicists’ will do it. Who knows? Why do I doubt?
    Because I read Smolin’s opinion: ‘ Not that every scientist
    is a seeker, most are not.’ (!) Ce la vie !
    #
    Now I must go to my farm, to my garden.
    I want to plant some trees and flowers today.
    =.
    All the best.
    Israel Sadovnik Socratus
    ====================.
    ==============================…    
    P.S.
    History.
    Einstein spent his life trying to construct a ‘unified field theory‘.
    He tried to explain electromagnetism using geometry just as he
    had done with gravity.
    De Broglie and Heisenberg tried to unite different forces
    using constants ( h) and ( h*).
    The year 2010: particle as a springy circle + ( h) and ( h*) +
    + Riemann geometry + nonlinear equations . . . . ?!?!
    P.S.
    ...the more a subject is understood,
    the more briefly it may be explained.
    / Thomas Jefferson,
    letter to Joseph Milligan, April 6, 1816 /
    #
    You do not really understand something unless
    you can explain it to your grandmother.
    / Albert Einstein /
    #
    And Rutherford said, if you understand something
    you can explain it to barmenwoman.
    #
    And somebody wrote : Of course , if I understand
    something I can explain it to my son.
    ====================================.
    ...

    israel socratus israel socratus
    Oct. 20, 2010 at 6:21am
  • Hi This is really a good information for home science students and please suggest some more sites related to this topic.

    Thanks & Regards

    Viagra Prix
    coolin james coolin james
    Oct. 28, 2010 at 6:37am
  • well, how about a light dark sensing particle? I have one somewhere, stored on a grain of rice.
    GARY PAINTER GARY PAINTER
    Dec. 12, 2010 at 12:42am
  • what if one were to measure the momentum of one particle and the position of another? could you not then calculate the momentum and velosity of one particle, given that the properties of an entangled pair correlate?
    Thomas Schwemberger Thomas Schwemberger
    Dec. 14, 2010 at 12:32am
  • Heisenberg and his Uncertainty principle.
    What is the ‘non – commutative’ algebra ?
    =========================== . .
    Any binary operator operating on two 'things' with different
    results if the order of the 'things' is reversed.
    That is, for 'things' a and b and operator a*b not equal to b*a.
    Why?
    Because ‘one’ can be different from ‘one’.
    For example.
    Take electron- symbol (e)
    Take proton - symbol (p)
    They are absolutely different particles.
    And interaction between electron and proton (!)
    is not the same than interaction between
    proton and electron (!):
    ep ≠ pe ( non - commutative algebra,
    Heisenberg and his Uncertainty principle.)
    #
    Another example:
    A thing called 'shoe' and a thing called 'sock'
    along with the operator 'and' which combines 'shoe' and 'sock' things.
    If you play around with it, you will find that the * order * is fairly important.
    ==========..
    P.S.
    We used to think that if we knew one, we knew two,
    because one and one are two. We are finding
    that we must learn a great deal more about `and '.
    / Sir Arthur Eddington /
    israel socratus israel socratus
    Jan. 23, 2011 at 10:22am
  • Many things are uncertain, but SPAM is apparently certain.
    psych psych
    Feb. 2, 2011 at 6:33pm
  • Dear Science News,

    PLEASE provide us with a way to report spam and abusive or off-topic comments, and then remove them! This garbage is ruining the experience. I hate to say it, but it reflects negatively on the professionalism of Science News. Perhaps you should only allow actual subscribers to post.
    Dr. Momus A. Morgus Dr. Momus A. Morgus
    Feb. 9, 2011 at 1:28pm
  • well but what about the fact that "connected memory" affects the particle (every measurement affects the observed object) and still only one parameter remains and the other one changes as we read out the first one, just like with the "wave of probability" the parameter changes as the wave will affect the "memory". Heissenberg pointed this problem in his book "Physics and Plilosophy".
    Bartlomiej Chrzanowski Bartlomiej Chrzanowski
    Feb. 21, 2011 at 3:32pm
  • Looking at Heisenberg's Uncertainty Principle and Quantum Information Theory as it relates to human communication. The 'Quantum' realm isn't 'quantum' at all. How can it be a measure of 'quantities' when there is no 'state' of matter? It's non-local and non-temporal, 'qualitative' not quantitative. All momentum and no position. a wave and not a particle. When something. moves, changes state, it must become less exact, loses definitive characteristics in exchange for transposition,(the uncertainty principle) it's 'qualities' are 'lost-in-translation'. So when a woman attempts to convey her thoughts. they are lost-in-translation, according to Heisenberg's principle and Quantum Information theory. Information that was originally massively dynamic had to be reduced to a quantum, (packet-ized) and conveyed loses it's qualities. 'My knowledge is limited to the 'words' I know and the 'definition' of those words."
    Xcythe Xcythe
    Oct. 14, 2011 at 10:23am
Registered readers are invited to post a comment. To encourage fruitful discussion, please keep your comments relevant, brief and courteous. Offensive, irrelevant, nonsensical and commercial posts will not be published. (All links will be removed from comments.)

You must register with Science News to add a comment. To log-in click here. To register as a new user, follow this link.

Follow Us