|
View: 26094|Reply: 56
|
[Edisi Fizik]
Apa anda tahu mengenai MEKANIK KUANTUM??
[Copy link]
|
|
|
Post Last Edit by dauswq at 13-2-2011 12:05
Physics experiment suggests existence of new particle
(PhysOrg.com) -- The results of a high-profile Fermilab physics experiment involving a University of Michigan professor appear to confirm strange 20-year-old findings that poke holes in the standard model, suggesting the existence of a new elementary particle: a fourth flavor of neutrin
The new results go further to describe a violation of a fundamental symmetry of the universe asserting that particles of antimatter behave in the same way as their matter counterparts.
Neutrinos are neutral elementary particles born in the radioactive decay of other particles. The known "flavors" of neutrinos are the neutral counterparts of electrons
and their heavier cousins, muons and taus. Regardless of a neutrino's original flavor, the particles constantly flip from one type to another in a phenomenon called "neutrino flavor oscillation."
An electron neutrino might become a muon neutrino, and then later an electron neutrino again. Scientists previously believed three flavors of neutrino exist. In this Mini Booster Neutrino Experiment, dubbed MiniBooNE, researchers detected more oscillations than would be possible if there were only three flavors.
"These results imply that there are either new particles or forces we had not previously imagined," said Byron Roe, professor emeritus in the Department of Physics, and an author of a paper on the results newly published online in Physical Review Letters.
"The simplest explanation involves adding new neutrino-like particles, or sterile neutrinos, which do not have the normal weak interactions."
The three known types of neutrino interact with matter primarily through the weak nuclear force, which makes them difficult to detect. It is hypothesized that this fourth flavor would not interact through the weak force, making it even harder to find.
The existence of sterile neutrinos could help explain the composition of the universe, said William Louis, a scientist at Los Alamos National Laboratory who was a doctoral student of Roe's at U-M and is involved in the MiniBooNE experiment.
"Physicists and astronomers are looking for sterile neutrinos because they could explain some or even all of the dark matter of the universe," Louis said. "Sterile neutrinos could also possibly help explain the matter asymmetry of the universe, or why the universe is primarily composed of matter, rather than antimatter."
The MiniBooNE experiment, a collaboration among some 60 researchers at several institutions, was conducted at Fermilab to check the results of the Liquid Scintillator Neutrino Detector (LSND) experiment at Los Alamos National Laboratory, which started in 1990. The LSND was the first to detect more neutrino oscillations than the standard model predicted.
MiniBooNE's initial results several years ago, based on data from a neutrino beam (as opposed to an antineutrino beam), did not support the LSND results. The LSND experiment was conducted using an antineutrino beam, though, so that was the next step for MiniBooNE.
These new results are based on the first three years of data from an antineutrino beam, and they tell a different story than the earlier results. MiniBooNE's antineutrino beam data does support the LSND findings. And the fact that the MiniBooNE experiments produced different results for antineutrinos than for neutrinos especially astounds physicists.
"The fact that we see this effect in antineutrinos and not in neutrinos makes it even more strange," Roe said. "This result means even more serious additions to our standard model would be necessary than had been thought from the first LSND result."
The result seems to violate the "charge-parity symmetry" of the universe, which asserts that the laws of physics apply in the same ways to particles and their counterpart antiparticles. Violations of this symmetry have been seen in some rare decays, but not with neutrinos, Roe said.
While these results are statistically significant and do support the LSND findings, the researchers caution that they need results over longer periods of time, or additional experiments before physicists can rule out the predictions of the standard model. Last edited by dauswq on 30-3-2013 01:49 AM
|
Rate
-
1
View Rating Log
-
|
|
|
|
|
|
|
|
|
|
|
MEKANIK KUANTUM Chptr 2: Hukum Ketidakpastian Heseinberg
Post Last Edit by dauswq at 14-1-2011 09:50
Blog: Heisenberg’s uncertainty principle still certain
Despite rumors to the contrary, a mainstay of quantum physics is just as (un)certain as ever.
By Laura Sanders
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. |
|
|
|
|
|
|
|
|
|
|
|
|
bidang ni termaktub dalam kategori HIGH PHYSICS ENERGY dlm fizik |
|
|
|
|
|
|
|
|
|
|
|
klu dulu org bersusah payah nak carik neutron, electron & proton
skrg ni,
neutrino pulak... ...
dauswq Post at 3-11-2010 06:50 
en dauswg,,,kirenye neutrino ni dtng nye dri cahaya matahari,,bergerak dari matahari hingga ke "ujung" alam semesta la tanpa henti? sbb x de collission..ke cane? kureng sket bab2 ni... |
|
|
|
|
|
|
|
|
|
|
|
Post Last Edit by dauswq at 6-11-2010 10:07
en dauswg,,,kirenye neutrino ni dtng nye dri cahaya matahari,,bergerak dari matahari hingg ...
motolumbe Post at 6-11-2010 08:11 
yes...ade org tanya gak 
ok...let me explain
Pertimbangkan 2 situasi:
Mamat ni berlari ke dinding..apa yg berlaku???
..
...
kelapa terhantuk ke dinding..
reason:: common sense & naturally mmg bdn kita tidak boleh lepas wall tersebut..
Ini disebabkan 2 medium yg berbeza ketumpatan...(udara & pepejal)
Dalam bidang fizik,
situasi berikut boleh dijelaskn dengan 3 teori klasik mekanik:
1. Teori Keabadian Momentum
halaju (v) yang terhasil dari gerakan mamat tersebut + jisim badannya
menyebabkan terhasilnya "momentum"
momentum = halaju x jisim
apabila satu jasad bertemu satu jasad lain,
pelanggaran berlaku....(badan mamat ni --> dinding)
lalu terhasillah benjol di kepala
Kenapa benjol terhasil??
sebab resultant momentum dari pertemuan 2 jasad itu..
Ok...kita dapat simpulkan
pelanggaran berlaku disebabkan momentum
tetapi yang sadisnya
mamat tak lepas jugak menembusi dinding itu..
cuma boleh pecahkan dinding, jatuhkan dinding ataupun menyebabkan benjol di kepala sahaja
2. Hukum Gerakan Newton ke-3
- keseimbangan daya antara 2 arah yang berlainan.
- daya yang diberikan oleh jasad A = daya diterima oleh jasad B.
Applying dalam situasi di atas;
Badan yang mempunyai halaju, jisim menghasilkan daya impulse ,
Daya= Jisim x Pecutan = Jisim X(Halaju/masa) = Momentum/Masa
Momentum mamat tadi sebenarnya menghasilkan daya impulse yang besar..
Daya ini kemudiannya diseimbangkan oleh daya dinding tersebut..
Kenapa dinding tidak bergerak??
..kerana daya impulse mamat itu tidak cukup kuat menandingi daya mencancang dinding tersebut,
seterusnya memberikan pulangan jumlah daya yang sama kepada mamat itu & menyebabkan benjol di kepala
3. Tenaga kinetik vs tenaga diam (the most important one!!! sebab saya nak relate ngan situasi 2)
Tenaga kinetik di hasilkan disebabkan halaju bertambah apabila menghampiri dinding.
K = 1/2 mv^2
Dinding juga mempunyai tenaga diam, tenaga yang disimpan...
Dalam bidang fizik mekanik klasik,
ia agak sukar tuk kira resultant energy yang terhasil daripada pelanggaran..
kita boleh simpulkan apabila dinding tidak bergerak wlpn dilanggar & bdn melantun ke belakang
kerana: tenaga diam >>>> tenaga kinetik
that how we explain based on classical mechanic...
Partikel lain - alpha, electron, photon (cahaya matahari), neutrino dsb
Camne plak ngan partikel di atas yang boleh menembusi dinding???
Bolehkah kita explen ngan teori klasik mekanik??
How??
1. Teori Keabadian Momentum
Momentum neutrino bertemu ngan momentum badan, sepatutnya berpatah balik SAHAJA bukannya boleh tembus badan..
keje giler ni..camne leh lepas badan:@.kan? kan? kan?
oleh itu, cannot explain by using teori keabadian momentum
2. Hukum Gerakan Newton ke-3
Daya yang dihasilkan neutrino >>> daya yang disepatutnya dipulang oleh badan,
sebab itu neutrino boleh lepas badan
doesn't make a sense:re:...cannot explain gak
3. Tenaga
Ada perubahan tenaga berlaku semasa neutrino menyinar ke bumi? TIDAK..so tenaga kinetik tak boleh pakai
tapi kita guna jumlah tenaga...E= K + V , V ialah tenaga keupayaan manakala K=Kinetik energy
E yang dimiliki neutrino kemudiannya melepasi badan manusia...
kerana?
mungkin tenaga dalam badan kurang daripada jumlah tenaga yang dimiliki oleh partikel itu..
sebab itu ia boleh lepas..yes, it could be
but how we explain?? tak bolehlar pki teori klasik mekanik camni..."ai tak mampu"
yang boleh kita simpulkan, E > tenaga badan manusia..sebab itu dia boleh lepas 
Cahaya ditujukan kepada prisma,
selepas sahaja cahaya tersebut bertemu ngan 2 medium berbeza (udara --> pepejal)
halaju cahaya c berkurang, seterusnya sinaran cahaya terbias...
tetapi tiada cahaya yang terpantul...dan ia boleh berlaku kalau cermin dihadang ngan bahan logam
sebab tak boleh dah explain pakai teori abadi momentum + daya ...so apa yg mereka tahu halaju yg berkurang dlm prisma
menyebabkan cahaya terpesong terbias...
tiada bukti yang cahaya ini ialah partikel - kata saintis sebelum era 20-an
that how we explain by classical way..
satu pendapat mengatakan
cahaya ialah gelombang elektromagnetik...
sebab tu ia boleh lepas apa2 medium...kerana mana2 gelombang seperti X-ray, gamma ray boleh sahaja melepasi apa2 medium
so mereka deduce cahaya ialah "gelombang elektromagnetik"
Okay..
now Einstein pulak menyibuk
dia suruh anggap cahaya sebagai partikel - "photon"
saintis mula mengelabah ..apa nih Einstein?? mana boleh partikel tembus satu jasad yang berbeza ketumpatan!!!!..
Ikut teori klasik mekanik, partikel hanya boleh patah balik SAHAJA..that's it!!!
"Gelombang" sahaja boleh lepas...cannot 3x be happened! it is classically forbidden MARAH saintis2 masa tu
Pastu De Broglie datang pulak 'back-up' Einstein,
Dia kata partikel boleh bersifat seperti "gelombang" pada suatu ketika,
Seperti yang kita tahu,
Gelombang ada "wavelength" dan "frequency"
Dia simpulkan "wavelength" adalah berkadar songsang ngan momentum , 
dan "momentum" itulah kemudiannya menerangkan cahaya bukan sekadar gelombang
tetapi ia juga ialah "partikel", dan sebab itu juga ia boleh lepas badan manusia di samping dirinya yang bertindak sebagai partikel yang membawa tenaga, E.
Kesimpulan dari Situasi 2
-Anggap cahaya sebagai partikel - iaitu "photon"
-Partikel boleh bersifat seperti "gelombang" pada satu masa.
-Gelombang boleh melepasi kesemua medium.
Manakah teori yang sesuai untuk explain "neutrino" ?
1. Situasi 1? -teori klasik mekanik - "CLASSICAL MECHANIC"
atau
2. Situasi 2? - new theory - " QUANTUM MECHANIC"
Jawapannya adalah Situasi ke-2...
Kesimpulannya....
Neutrino adalah sejenis partikel yang dibebaskan oleh matahari...neutrino bergerak melepasi ruang vakum menuju kebumi
dengan membawa tenaga, E..
Apabila neutrino jumpa badan manusia kita, dia tak fikir panjang, main tembus je...
tapi sebahagiannya ada yang terpantul...
sebab neutrino boleh tembus ialah kerana dia boleh bersifat "gelombang"
"gelombang" boleh tembus badan kita bila2 masa sahaja..
Dalam bidang fizik, fenomena ini boleh dibuktikan dengan menggunakan Schrodinger Equation,
di mana "gelombang" terhasil dari neutron
ialah dalam bentuk "wave funtion" -
dari situ juga dapat explen apa yang berlaku kepada neutrino apabila dia menembusi badan manusia
kita tak boleh explen pki "teori klasik mekanik" sahaja, sebab tak cukup maklumat,
sebenarnya jumlah "neutrino" yang masuk badan manusia akan berkurang (decaying)
maka, apabila dia keluar balik, gelombangnya akan jadi lebih rendah berbanding sebelum dia masuk...
tetapi semua ini ahanya boleh jelaskn melalui "QUANTUM MECHANIC"
that's all from me |
|
|
|
|
|
|
|
|
|
|
|
Reply 5# dauswq
waaahhhh...thanks,,many thanks,,,sudah clear!
so, neutrino behavior bleh explain pakai quantum of mechanic la..
ade stu persoalan lak timbul,,kirenye sume particle kat alam nyata ni,,bleh explain pakai quantum of mechanic ke?
cnthnye,,klu sebjik moto la,,,anggap sbgai particle yg besar,,bile bergerak,,ade momentum,,n ade wavelength jugak la ke? dlm kes ni,,wavelength kecil bangat smpi leh abaikn..haha..btol ke pemikiran ni.. |
|
|
|
|
|
|
|
|
|
|
|
Reply motolumbe
yes...kan saya ada tulis tu
partikel boleh bersifat seperti gelombang..
...
dauswq Post at 7-11-2010 02:39 
haha,,iye x ye...kelajuan cahay perlu dipertimbangkan...rasenye penemuan ni mungkin bleh "menerangkan" bagaimana malaikat yang tuhan cipta bleh bergerak dengn sngt pantas...
wallahuaallam.... |
|
|
|
|
|
|
|
|
|
|
|
Reply 8# motolumbe
betul...bagus fikir mcm tu |
|
|
|
|
|
|
|
|
|
|
|
|
oh my god such a very ______ topic. oh my god. thsis good man, really. |
|
|
|
|
|
|
|
|
|
|
|
Reply 10# mbhcsf
based on my knowledge...
but sometimes you know,
when we can't adapt to application,
we have no idea what the theory is all about
saya belaja teori Schrodinger, satu patah pun tak fhm - motifnya
mathnye je faham
but, after I related to some particles have mentioned above,
I understand more... |
|
|
|
|
|
|
|
|
|
|
|
Reply 11# pinklollipop
klu lolli ade ape2, just tanya je... |
|
|
|
|
|
|
|
|
|
|
|
|
dasat ko daus, kau research aku tukang applikasi jer |
|
|
|
|
|
|
|
|
|
|
|
|
so, maksudnya adekah halaju partikel tu tadi akan berkurangan bila menembusi sesuatu benda/medium, macam cahaya lalu dalam prism ? |
|
|
|
|
|
|
|
|
|
|
|
Post Last Edit by dauswq at 21-2-2012 18:53
so, maksudnya adekah halaju partikel tu tadi akan berkurangan bila menembusi sesuatu benda/medium, m ...
winamp05 Post at 16-11-2010 12:59
salam encik winamp dan sesiapa sahaja,
again , teori yg dimaksudkan ialah Quantum Mechanic...
dalam dunia mekanik kuantum,
partikel dijelaskan dengan "probability density" dalam bentuk "wave" equation.
kat sini,
kita tak boleh apply halaju ikut teori klasik mekanik..
yang boleh diapply ialah
momentum...kerana De Broglie kata -->  1.1
hanya momentum & tenaga E sahaja boleh menjelaskan jika berlakunya pengurangan halaju dalam mekanik kuantum
ok..
1. momentum, p = m d<x>/dt di mana <x> ialah expectation value (jumlah jarak) .
2. Kadar perubahan "expectation value/jarak" ialah halaju dalam erti kata klasik mekanik ( momentum = m v) dan hasilnya memberikan  1.2 dalam quantum mekanik.
3. Kita jelaskan perubahan halaju partikel dengan perubahan tenaga kinetik. Tenaga kinetik berubah bila Keupayaan, V diubah kerana E = V +K. Tenaga kinetik adalah ,  dan boleh ditukar kepada  bila ganti v = p/m . Maka, dalam kuantum mekanik, tenaga kinetik boleh ditulis sebagai  dan seterusnya gantikan persamaan 1.2 kepada p dalam K , hasilnya : . Berdasarkan maklumat ini, kita dapat kaitkan perubahan halaju dengan perubahan tenaga kinetik, seterusnya kita wujudkan
E = V+ K dalam Schrondinger eqn: 
dan selesaikan untuk mendapat "wave eqn".
4. Mengapakah halaju cahaja / bilangan partikel berkurang bila memasuki medium lebih tumpat?..
Medium berlainan ketumpatan ---> keupayaan yang berbeza
E = K + V, E ialah pemalar: Bila V bertambah, maka Tenaga kinetik berkurang...bila tenaga kinetik berkurang, maka halaju pun berkurang!!
V bertambah = medium yang lebih tumpat spt kaca dsb
5. Bagaimana anda nak tau halaju photon boleh kurang/ bilangan partikel berkurang?
Ibaratkan medium (cth: dinding). Manakah anda rasa akan tembus?
A Jerit??
B Tumbuk dinding??
Tumbuk dinding takkan lepas, malah tangan anda akan terasa sakit sbb tak lepas
Jerit--> anda dpt dengar suara di sebalik dinding...
Di sini, disimpulkan partikel/photon dalam bentuk "wave function" sahaja boleh lepas dinding tersebut yang merupakan halangan (Keupayaan = V dalam erti kata kuantum mekanik) ...
Oleh itu, menjawab persoalan winamp,
partikel tadi yang membawa tenaga , juga membawa momentum,
dijelaskan dalam bentuk "wave eqn"
di mana kita perolehi "wave eqn" dari persamaan di atas... [Rujuk Quantum Mechanic (3) ]
Untuk kes partikel, kita tak leh kata "halaju berkurang" tetapi "bilangan berkurang" kerana partikel tiada "special case" like photon (cahaya). Jadi, kita hanya boleh kata bilangan berkurang selepas menghadapi suatu rintangan.
Dalam kes proton, kenapa halaju berkurang??
Bak kata Einstein lagi,
Bila cahaya berada dalam "energy state" yang sama, cahaya diberi dalam bentuk bilangan n photons akan membebaskan "extra photons" yang mana ia berkadar langsung dengan (n+1).
Ini bermakna, cahaya dalam bentuk elektromagnetic waves perlu ditukar kepada n photons dengan membebaskan (n+1) bilangan photons berdasarkan penjelasan Einstein,..
Cahaya (Elektromagnetic wave) akan beradiasi kepada photon bila melalui medium yg berbeza ketumpatan di mana n --> n+1...
Penjelasan ini dapat dibuat, bila V ialah "harmonic osclillator" di mana
 V bukan lagik pemalar seperti yang berlaku kepada partikel lain...
Solving Schrondiger Eqn, kita dapat bilangan photon =
dan
 dan 
tengok eqn di atas,
spt yang di kata oleh Einstein, mmg ia kan hasilkan n+1...
Ikut logik,
bila photons berkurang sebab pembebasan..
apa terjadi ngan momentum?? p akan berkurang, seterusnya halaju cahaya pun berkurang///
settle |
|
|
|
|
|
|
|
|
|
|
|
Reply 14# allsparks
allsparks engineer bhgn mana? |
|
|
|
|
|
|
|
|
|
|
|
Reply 17# dauswq
aku projek engineer je bro, more on mechanical, civil and structure.
kadang2 klien ni pemalas, so aku kene antar proposal dan costing skali ,
projek belum tentu dapat walhal satu plant kite costingkan  |
|
|
|
|
|
|
|
|
|
|
|
Bila cahaya berada dalam "energy state" yang sama, cahaya diberi dalam bentuk bilangan n photons akan membebaskan "extra photons" yang mana ia berkadar langsung dengan (n+1).
apa itu energy stste ? |
|
|
|
|
|
|
|
|
|
| |
Category: Belia & Informasi
|
Post time 3-11-2010 06:36 AM
变色卡
Author
Post time 6-11-2010 08:11 AM
= 
