Higgs excitations near absolute zero

Jul 25, 2012
Illustration of the Higgs excitation in a two-dimensional system. The dynamics of the Higgs excitation (red sphere) is described by an oscillation in a ‘sombrero’-shaped potential. Graphic: MPQ, Quantum Many-Body Division

(Phys.org) -- A collaboration of physicists from Max Planck Institute of Quantum Optics, LMU, Harvard and Caltech detect Higgs-type excitations in a low-dimensional system of ultracold atoms at the transition between different phases of matter.

The sudden breaking of plays a fundamental role in physics, in particular for the description of that change the whole state of a system. One example is the spontaneous alignment of the atomic magnets in a that is cooled down below the . Being governed by such a “global order”, the system can be excited to a collective oscillation, in which all particles move in a coordinated way. If the collective behaviour follows the rules of relativity, a special kind of oscillation can develop, a so-call Higgs excitation (named after the British physicist Peter Higgs). Such an excitation plays a key role in the standard model of elementary particles, where it is called a Higgs-particle. Also, solid state-like systems can exhibit Higgs excitations, if the collective motion of the particles obeys rules that resemble those of the theory of relativity.

However, the detection of Higgs excitations is usually rather difficult, because the excitations typically decay in a short time. Moreover, they are expected to be especially short-lived in very flat, so-called low-dimensional systems and it has been a subject of theoretical debate whether they are observable at all in such geometries. Now, a team of from the Quantum Many-Body Division of the Max-Planck-Institute of together with theory colleagues from Harvard University and the California Institute of Technology succeeded in experimentally identifying Higgs excitations in a two-dimensional system of (Nature, July 26, 2012). “We are excited to study phenomena close to absolute zero temperature that usually occur at the highest energies”, Prof. Immanuel Bloch, leader of the Division, explains.

The experiment starts with cooling rubidium atoms down to temperatures near absolute zero. Then the ultracold atoms are loaded into a two-dimensional optical lattice, a checkerboard-like pattern of dark and bright regions of light that is produced by interfering laser beams. Ultracold atoms in such lattices offer the opportunity to realize different states of matter.

For very intense optical lattices (which means a very high contrast between dark and bright areas), a highly ordered state develops, a so-called Mott insulator (named after the British physicist Sir Neville Mott). In this state, each lattice site is occupied with exactly one single atom, which is fixed to its place. If the lattice intensity is decreased more and more, a phase transition to a superfluid takes place. In a superfluid, all atoms are part of a single field, which extends over the whole lattice and describes the collective motion of the system as one extended quantum mechanical wave. The dynamics of this quantum field follows the laws of an “effective” relativistic field theory, in which the speed of light is replaced by the speed of sound. When the system is brought out of equilibrium, collective oscillations in the form of Higgs excitations can be generated.

A fundamental challenge for the researchers has been to find out whether Higgs excitations can survive even in a two-dimensional system, and if so, how they can be detected. To answer these questions, the scientists set the system parameters such that the quantum gas is very close to the described transition from a superfluid to a Mott insulator. Then, for several milliseconds, the lattice intensity is gently modulated. This modulation is expected to create a few Higgs excitations, while minimally disturbing the system. “We shake the system only very gently to avoid undesired side effects. Otherwise, we could not isolate the signal of the Higgs excitations”, Manuel Endres, one of the senior researchers on the project, points out. “We are able to measure the temperature of the system with a precision of a billionth of a Kelvin using an extremely sensitive method developed in our group. With this method, we could detect small peaks in the temperature distribution at certain values of modulation frequencies.”

The researchers interpret their observations in the following way: Once the frequency of the intensity modulation matches the oscillation frequency of a Higgs excitation, the generation of Higgs excitations is resonantly enhanced. In this situation, more energy is transferred to the system which leads to a rise in its temperature. The experimental data show a clear shift to lower oscillation frequencies when the transition to a Mott insulator is approached. “We talk about a ‘softening’ of the Higgs excitation, which is characteristic of their collective behaviour in the vicinity of the quantum phase transition,” Manuel Endres points out.

It has been a subject of theoretical debate whether Higgs exist at all in such a system, and if so, what their precise properties are. “We have detected a phenomenon which, at present, cannot be precisely calculated. This makes the experimental observation even more important”, Manuel Endres says.

Explore further: Hide and seek: Sterile neutrinos remain elusive

More information: Manuel Endres, Takeshi Fukuhara, David Pekker, Marc Cheneau, Peter Schauß, Christian Groß, Eugene Demler, Stefan Kuhr, and Immanuel Bloch The 'Higgs' Amplitude Mode at the Two-Dimensional Superfluid-Mott Insulator Tran-sition Nature, 26. July, 2012

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PoppaJ
1.8 / 5 (5) Jul 25, 2012
Experimental observation of the Higgs particle? What a leap from "we have evidence that this particle decay could have come from a Higgs." To "Oh there it is in a bottle for all to see." This is huge is it not?
Pyle
4.6 / 5 (5) Jul 25, 2012
Huge? Sure, if their guess as to what they have observed is correct. Many is the time, though, that what we think we are looking at is in fact something very different and not as exotic as some theory might suggest. Look to the Pioneer Anomaly as a recent example.
vacuum-mechanics
1 / 5 (8) Jul 25, 2012
The sudden breaking of symmetry plays a fundamental role in physics, ... One example is the spontaneous alignment of the atomic magnets in a ferromagnetic material that is cooled down below the Curie-temperature. .. a special kind of oscillation can develop, a so-call Higgs excitation. Such an excitation plays a key role in the standard model of elementary particles, where it is called a Higgs-particle.


It is interesting to note that, there is no detail about Higgs here, as if it is well known. But actually, it seems that peoples who work with it still do not know what it is, how it was excited? This is the reason that someone says, it is the old aether which was not being accepted before (see below).
http://www.vacuum...mid=9=en
barakn
4.5 / 5 (8) Jul 25, 2012
Please note that this is not the Higgs boson being discussed, but the Higgs name attached to something else.
vega12
5 / 5 (5) Jul 26, 2012
Please note that this is not the Higgs boson being discussed, but the Higgs name attached to something else.

Exactly. The Higgs symmetry breaking mechanism is a very general property that quantum systems can have. The Higgs boson of the standard model, is one specific such mechanism that is used to explain mass and electroweak symmetry breaking that is observed in nature. The Higgs used in this article is not related to the Higgs boson particle of the standard model.
ant_oacute_nio354
1 / 5 (9) Jul 26, 2012
Higgs doesn't exist.
The mass is the electric dipole moment.
Satene
3 / 5 (2) Jul 26, 2012
It is interesting to note that, there is no detail about Higgs here, as if it is well known. But actually, it seems that peoples who work with it still do not know what it is, how it was excited? This is the reason that someone says, it is the old aether which was not being accepted before (see below).
Apparently the mechanism in which W/Z bosons are gaining mass is similar to mechanism, in which the lighter bosons (including photons) gain mass. But to search for the Higgs excitation (Ehiggs = 126 GeV) at the absolute zero temperature (Ezpe = nanoeV) sounds somewhat strange for me. I'd talk about CMBR noise or something similar at the zero temperature.
Satene
3 / 5 (2) Jul 26, 2012
Note that CMBR noise isn't completely scale invariant, it exhibits a maximum at the roughly 1.73 cm wavelength, which corresponds the temperature of 2.72548 ± 0.00057 K K and binding energy of about 0.25 eV. The Big Bang model extrapolates the well known 13,7 Gyrs age of the Universe from this value. Therefore in the quantum noise the excitations of this energy would be slightly preferred.
hemitite
2.3 / 5 (3) Jul 26, 2012
ant_oacute_nio354 ,

In fact Higgs himself doesn't exist: "he" is a corporate construct like Betty Crocker foisted on an ignorant public by the greedy power mad forces of Big Science!
Torbjorn_Larsson_OM
5 / 5 (2) Jul 26, 2012
But this is now important work, since we now the universal scalar field of the Higgs mechanism exist and we suspect that the similar universal scalar field of inflation existed before that. In fact, these Higgs excitation analogs were just proposed as spontaneous aggregating in early inflation and to possibly leave an imprint in the CMB. (They only existed for a 2 order of magnitude inflation expansion though, while inflation caused a 60 oom expansion.)

@ aon354: The higgs mechanism likely exist, since a higgs like particle was just announced by the LHC. It is unlikely it is something else since the visible higgs boson were excluded everywhere else, it is likely a boson due to its decays (or it would be a graviton spin 2 analog - unlikely), it is likely a standard higgs due to its production rates in various decays.

You can argue that a higgs mechanism doesn't exist, but there is no observation to test it and the observations we have will most likely test the higgs theory.
Torbjorn_Larsson_OM
not rated yet Jul 26, 2012
@ Satene:

You mean, in the photonic noise, since CMB is photons.

No, gravity isn't anything like the higgs that gives many fundamental particles mass. Higgs isn't really all linear, because it doesn't give photons or gluons mass, and its own free boson it gives a mass non-proportional to the others (or we wouldn't need to search for it). Finally it gives Ws/Zs mass due to binding with the other 3 of its 4 bosons.
Pyle
3.4 / 5 (5) Jul 26, 2012
since we now (know) the universal scalar field of the Higgs mechanism exist
Nonsense. Just like the Pioneer Anamoly obviously demonstrated that the Aether existed and Mercury's wobble demonstrated the existence of the planet Vulcan. The observation is consistent with the Higgs mechanism, but it is only one data point. Let's just say the Higgs mechanism isn't disproved by this experiment.

since a higgs like particle was just announced by the LHC
Again. The results didn't exclude a Higgs boson, but other explanations exist. Here is an alternative http://arxiv.org/...4702.pdf I am sure there are more.

(Just playing devil's advocate.)
ewj
1 / 5 (2) Jul 27, 2012
Mercury's wobble demonstrated the existence of the planet Vulcan.
The ebb and flow of tides was caused by the rotation of the moon. In both these examples proved that information exists between them. In the case of sun spots on all neighbouring suns: " are they simultaneous"? if so then there is information in space and detected by the frequency simultaneity of sun spots. When are we going to advised? This is the case or not. IF they are simultaneous ( permitting for the velocity of expansion ( not velocity of light ). Then we will know we exist in a space with 4 real spatial dimensions. The expansion providing the Primary dimension into which the other 3 can exist. Then the production - that is the association of atoms from background energy is obvious applying Max planks theory. The speed of light just so happens to be constant at this phase and part of the universe. In a book 'Absolute relativity theory of everything'.
technodiss
not rated yet Jul 29, 2012
"The dynamics of this quantum field follows the laws of an effective relativistic field theory, in which the speed of light is replaced by the speed of sound."
now, when they say 'speed of sound', what velocity are they talking about? sound waves travel differently in fluids, solids, and gasses with density of the medium being a factor. how fast does sound move in a super fluid?