State/observable interactions using basic geometric algebra solutions of the Maxwell equation Alexander SOIGUINE1 1 SOiGUINE
Quantum Computing, Aliso Viejo, CA 92656, USA
http://soiguine.com Email address:
[email protected]
Abstract: Maxwell equation in geometric algebra formalism with equally weighted basic solutions is subjected to continuously acting Clifford translation. The received states, operators acting on observables, are analyzed with different values of the Clifford translation time factor and through the observable measurement results.
1. Introduction Letβs consider special case of g-qubits [1] [2]: πΌ + π½π΅1 + πΌπ΅2 + π½π΅3 = πΌ + π½π΅3 + (πΌ + π½π΅3 )π΅2
(1.1)
with basic bivectors satisfying usual anticommutative multiplication rules: π΅1 π΅2 = βπ΅3 , π΅1 π΅3 = π΅2 , π΅2 π΅3 = βπ΅1 . The normalization in this case is: πΌ 2 + π½2 + πΌ 2 + π½2 = 1 βΉ πΌ 2 + π½2 =
1 2
2
2
(β2πΌ) + (β2π½) = 1
or
1
With this normalization β2πΌ = cos π for some angle π. Then Ξ² =
β2
sin π, Ο = cos β1 (β2πΌ).
The state (1.1) is one possible lift of conventional quantum mechanical qubit (πΌ+ππ½ ) with πΌ+ππ½ 1
πΌ 2 + π½2 = 2, when complex plane is specified as the plane of π΅3 . Write state (1.1) in exponential form: πΌ + π½π΅1 + πΌπ΅2 + π½π΅3 = π πΌπ΅ π , π = πππ β1 (β2πΌ), πΌπ΅ =
π½ β1β2πΌ 2
π΅1 +
(1.2) πΌ
β1β2πΌ2
π΅2 +
π½ β1β2πΌ2
π΅3
Apply Clifford translation in the plane of π΅3 to (1.2) (see, for example [3]): π πΌπ΅3 πΎ π πΌπ΅ π = πππ πΎ πππ π + π ππ πΎ π ππ π (πΌπ΅3 β
πΌπ΅ ) + π ππ πΎ πππ π πΌπ΅3 + πππ πΎ π ππ π πΌπ΅ + π ππ πΎ π ππ π πΌπ΅3 β§ πΌπ΅ =
1
πππ πΎ πππ π β
π½
π½
πππ πΎ π ππ π π΅1 β1 β 2πΌ 2 β1 β 2πΌ 2 πΌ π½ π½ + πππ πΎ π ππ π π΅2 + πππ πΎ π ππ π π΅3 + π ππ πΎ π ππ π π΅2 β1 β 2πΌ 2 β1 β 2πΌ 2 β1 β 2πΌ 2 πΌ + π ππ πΎ π ππ π π΅1 = β1 β 2πΌ 2
πππ πΎ πππ π β
π ππ πΎ π ππ π + π ππ πΎ πππ π π΅3 +
π½
π½ πΌ π ππ πΎ sin π + ( πππ πΎ π ππ π + π ππ πΎ π ππ π) π΅1 β1 β 2πΌ 2 β1 β 2πΌ 2 β1 β 2πΌ 2 πΌ π½ +( πππ πΎ π ππ π + π ππ πΎ π ππ π) π΅2 β1 β 2πΌ 2 β1 β 2πΌ 2 π½ + (π ππ πΎ πππ π + πππ πΎ π ππ π) π΅3 β1 β 2πΌ 2
This will be used later for the g-qubits generated by Maxwell equation. To make the following text more comprehensive letβs briefly recall how the system of the electromagnetic Maxwell equations is formulated as one equation in geometric algebra terms [4]. β , where πΌ3 is righthand screw unit Take geometric algebra element of the form: πΉ = πΈβ + πΌ3 π» volume in the three dimensions. The electromagnetic field πΉ is created by some given distribution of charges and currents, also written as geometric algebra multivector: π½ β‘ π β π. Apply operator ππ‘ + β to πΉ. The result will be: β )+β β + πΌβ β (ππ‘ + β)πΉ = ββ β πΈβ + π β β§ πΈβ + πΌ3 ππ‘ π» 3 (β β
π» ) βπ‘ πΈβ + πΌ3 (β β§ π» π πππππ
πππ£πππ‘ππ
π£πππ‘ππ
Comparing component wise (ππ‘ + β)πΉ and π½ we get: π» β πΈβ β‘ πππ£πΈβ = π β ) β‘ ππ‘ πΈβ β πππ‘π» β = βπ ππ‘ πΈβ + πΌ3 (π» β§ π» β β‘ πΌ3 πππ‘πΈβ + πΌ3 ππ‘ π» β =0 π» β§ πΈβ + πΌ3 ππ‘ π» β ) β‘ πΌ3 (πππ£π» β)=0 πΌ3 (π» β
π» { Thus, we have usual system of Maxwell equations: πππ£πΈβ = π β = βπ ππ‘ πΈβ β πππ‘π» β + πππ‘πΈβ = 0 ππ‘ π» β =0 { πππ£π»
equivalent to one equation (ππ‘ + β)πΉ = π½ Without charges and currents the equation becomes (ππ‘ + β)πΉ = 0 2
ππ ππ’πππ πππππ
Arbitrary linear combination of the two basic solutions of the above Maxwell equation in geometric algebra terms is [5]: +
β
+
ππ πΌπππππ π + ππ πΌπππππ π
β
(1.3)
where π Β± = cosβ1 (
1
β2
Β± πΌπππππ = πΌπ
cos π(π‘ β [(πΌ3 πΌπ ) β π])),
π πππ(π‘ β [(πΌ3 πΌπ ) β π])
+πΌπ΅0
πππ π(π‘ β [(πΌ3 πΌπ ) β π])
β1 + π ππ2 π(π‘ β [(πΌ3 πΌπ ) β π]) β1 + π ππ2 π(π‘ β [(πΌ3 πΌπ ) β π]) π πππ(π‘ β [(πΌ3 πΌπ ) β π]) + πΌπΈ0 β1 + π ππ2 π(π‘ β [(πΌ3 πΌπ ) β π])
The triple of unit value basis orthonormal bivectors {πΌπ , πΌπ΅0 , πΌπΈ0 } is comprised of πΌπ bivector, dual, thatβs received by applying righthand screw unit volume πΌ3 , to the propagation direction vector, πΌπ΅0 is dual to initial vector of magnetic field, πΌπΈ0 is dual to initial vector of electric field. The expression (1.3) is linear combination of two geometric algebra states, g-qubits [1], [2], and can particularly be transformed by a Clifford translation, geometric algebra lift of matrix Hamiltonian action on two-dimensional complex vectors, qubits in terms of conventional quantum mechanics. 0 2ππΎ Suppose conventional matrix Hamiltonian is ( ). Its geometric algebra lift makes β2ππΎ 0 rotation of the state (1.3) in the πΌπΈ0 plane by angle 2πΎ1 and the lift is π 2πΎπΌπΈ0 . One interesting example of the current formalism is calculating the Berry potential +
+
β
β
associated with (1.3) state transformation π 2πΎπΌπΈ0 (ππ πΌπππππ π + ππ πΌπππππ π ): +
π 2πΎπΌ + β + β π πΈ0 (ππ πΌπππππ π + ππ πΌπππππ π ) ππΎ + + β β + β βπΌπππππ π+ βπΌπππππ πβ = (ππ + ππ )π β2πΎπΌπΈ0 (β2π 2πΎπΌπΈ0 )(ππ πΌπππππ π + ππ πΌπππππ π ) +
β
β
π΄(πΎ) = (ππ βπΌπππππ π + ππ βπΌπππππ π )π β2πΎπΌπΈ0 πΌπΈ0 +
+
β
β
β
β
+
+
= (β2) (π2 + π 2 + ππ(π βπΌπππππ π π πΌπππππ π + π βπΌπππππ π π πΌπππππ π )) If the two basic solutions are equally weighted, Ξ» = ΞΌ, we get a potential, instantly nonlocally spread in three-dimensional space and independent of time, and, up to electric/magnetic field amplitude value, the potential is2:
The same result takes place if Clifford translation makes rotation in the plane of πΌπ΅0 Contrary to conventional quantum mechanics formalism where states, particularly qubits, are only defined up to a phase, the geometric algebra with variable complex plane paradigm is much deeper theory, thus the statement that Berry potential is not observable due to gauge redundancy makes here no sense 1 2
3
π΄(πΎ)|π=π ~ β πππ 2 [(πΌ3 πΌπ ) β π] It is scalar field, thus invariant in any πΊ3+ measurements [1].
2. Clifford translation continuously acting on a state received as the Maxwell equation solution +
β
+
β
Letβs initially calculate ππ πΌπππππ π + ππ πΌπππππ π assuming again Ξ» = ΞΌ, say both are equal to 1. +
+
β
β
π πΌπππππ π + π πΌπππππ π 1 1 = cos π(π‘ β [(πΌ3 πΌπ ) β π]) + πΌπ π πππ(π‘ β [(πΌ3 πΌπ ) β π]) β2 β2 1 1 + πΌπ΅0 πππ π(π‘ β [(πΌ3 πΌπ ) β π]) + πΌπΈ0 π πππ(π‘ β [(πΌ3 πΌπ ) β π]) β2 β2 1 1 + cos π(π‘ + [(πΌ3 πΌπ ) β π]) + πΌπ π πππ(π‘ + [(πΌ3 πΌπ ) β π]) β2 β2 1 1 + πΌπ΅0 πππ π(π‘ + [(πΌ3 πΌπ ) β π]) + πΌπΈ0 π πππ(π‘ + [(πΌ3 πΌπ ) β π]) β2 β2 2 = cos π([(πΌ3 πΌπ ) β π]) (cos ππ‘ + πΌπ sin ππ‘ + πΌπ΅0 cos ππ‘ + πΌπΈ0 sin ππ‘) β2 +
β
+
β
We see that the state π πΌπππππ π + π πΌπππππ π has the form of (1.1) considered in Introduction, thus the results for the Clifford translation obtained there can be applied. Suppose that the angle in the above Clifford translation continuously changes in time, πΎ = ππ π‘. Then Clifford translation with πΌπ» = πΌπΈ0 and |π»| = 2πΎ gives: +
+
β
+
β
+
β
β
π πΌπ» |π»|π‘ (ππ πΌπππππ π + ππ πΌπππππ π )|Ξ»=ΞΌ=1 = π 2πΌπΈ0 ππ π‘ (π πΌπππππ π + π πΌπππππ π ) = πππ 2 ππ π‘ πππ π π½ β π ππ 2ππ π‘ sin π β1 β 2πΌ 2 π½ πΌ +( πππ 2ππ π‘ π ππ π + π ππ 2ππ π‘ π ππ π) π΅1 β1 β 2πΌ 2 β1 β 2πΌ 2 πΌ π½ +( πππ 2ππ π‘ π ππ π + π ππ 2ππ π‘ π ππ π) π΅2 β1 β 2πΌ 2 β1 β 2πΌ 2 π½ + (π ππ πΎ2ππ π‘ πππ π + πππ 2ππ π‘ π ππ π) π΅3 β1 β 2πΌ 2 where πΌ =
2 β2
πππ π([(πΌ3 πΌπ ) β π]) πππ ππ‘ and π½ =
2 β2
After some trigonometry the result is:
4
πππ π([(πΌ3 πΌπ ) β π]) π ππ ππ‘
+
β
+
β
π 2πΌπΈ0 ππ π‘ (π πΌπππππ π + π πΌπππππ π ) 2
cos[(πΌ3 πΌπ ) β π] {cos(2ππ π‘ + ππ‘) + sin(2ππ π‘ + ππ‘)πΌπΈ0 β2 + [cos(2ππ π‘ + ππ‘) + sin(2ππ π‘ + ππ‘)πΌπΈ0 ]πΌπ΅0 } =
We see that action of the Clifford translation π 2πΌπΈ0 ππ π‘ on the general solution constructed as equal weight sum of basic solutions of the Maxwell equation gives, up to the space location defined factor, the state which is the sum of rotation in the plane of πΌπΈ0 by angle 2ππ π‘ + ππ‘ plus the same rotation followed by flip around plane of πΌπΈ0 . It can also be read as a single πΊ3+ element: +
+
β
β
π 2πΌπΈ0 ππ π‘ (π πΌπππππ π + π πΌπππππ π ) = 2 πππ [(πΌ3 πΌπ ) β π] π πΌπ
π where π = πππ β1 (
1
β2
1
πΌπ
=
β2
πππ (2ππ π‘ + ππ‘))
π ππ(2ππ π‘ + ππ‘)πΌπ +
1 β2
(2.1)
πππ (2ππ π‘ + ππ‘)πΌπ΅0 +
1 β2
π ππ(2ππ π‘ + ππ‘)πΌπΈ0
(2.2)
3. Measurement of an observable Though the Clifford translation result received above is linear combination of two geometric 1 0 algebra states corresponding to some conventional qubits π1 ( ) and π2 ( ) (see, for 0 1 example [5]), measurement of a πΊ3 valued observable is not linear combination of measurements by those states because measurement in the currently used formalism does not follow the distributive law. So, we need to use general formula, the geometric algebra variant of the Hopf fibration (see [2], Sec.5.1): If we have a state πΌ + π½1 π΅1 + π½2 π΅2 + π½3 π΅3 , πΌ 2 + π½12 + π½22 + π½32 = 1, and observable πΆ0 + πΆ1 π΅1 + πΆ2 π΅2 + πΆ3 π΅3 then the result of measurement is: πΌ+π½1 π΅1 +π½2 π΅2 +π½3 π΅3
πΆ0 + πΆ1 π΅1 + πΆ2 π΅2 + πΆ3 π΅3 β πΆ0 2) 2 2 )] 2 [(πΌ (π½ + (πΆ1 + π½1 β 2 + π½3 + 2πΆ2 (π½1 π½2 β πΌπ½3 ) + 2πΆ3 (πΌπ½2 + π½1 π½3 ))π΅1 + (2πΆ1 (πΌπ½3 + π½1 π½2 ) + πΆ2 [(πΌ 2 + π½22 ) β (π½12 + π½32 )] + 2πΆ3 (π½2 π½3 β πΌπ½1 ))π΅2 + (2πΆ1 (π½1 π½3 β πΌπ½2 ) + 2πΆ2 (πΌπ½1 + π½2 π½3 ) + πΆ3 [(πΌ 2 + π½32 ) β (π½12 + π½22 )])π΅3 In the current case: π΅1 = πΌπ , π΅2 = πΌπ΅0 , π΅3 = πΌπΈ0 , πΌ=
1 β2
π½1 =
πππ (2ππ π‘ + ππ‘),
1 β2
π ππ(2ππ π‘ + ππ‘), π½2 =
1 β2
πππ (2ππ π‘ + ππ‘), π½3 =
1 β2
π ππ(2ππ π‘ + ππ‘)
and then the result of measurement (without the distance factor 4πππ 2 [(πΌ3 πΌπ ) β π] ) is: πΆ0 + πΆ3 πΌπ + (πΆ1 sin 2(2ππ π‘ + ππ‘) + πΆ2 cos 2(2ππ π‘ + ππ‘))πΌπ΅0 + 5
(βπΆ1 cos 2(2ππ π‘ + ππ‘) + πΆ2 sin 2(2ππ π‘ + ππ‘))πΌπΈ0
(3.1)
Geometrically, it means the following: -
-
The observable in the measurement by π πΌπ
π , π and πΌπ
defined in (2.1) and (2.2), is rotated counterclockwise by πβ2 around the axis dual to πΌπ΅0 , thus the observable third bivector component of the value πΆ3 becomes lying in πΌπ and does not further change; Two other components, with initial values πΆ1 and πΆ2 in the planes of πΌπ and πΌπ΅0 , become orthogonal to πΌπ and rotate clockwise around axis dual to πΌπ with angle πβ β 2(2π π‘ + ππ‘)3. π 2
Like in above simple example of Berry potential, the result of measurement, including the factor 4πππ 2 [(πΌ3 πΌπ ) β π], spreads through the whole space at any instant of time.
4. Conclusions It was shown that for the special case of g-cubit states that particularly appear as solutions of the Maxwell equation in geometric algebra terms the result of measurement of any πΊ3 valued observable is spread through the whole three-dimensional space at any instant of time.
Works Cited
[1] A. Soiguine, "Geometric Algebra, Qubits, Geometric Evolution, and All That," January 2015. [Online]. Available: http://arxiv.org/abs/1502.02169. [2] A. Soiguine, Geometric Phase in Geometric Algebra Qubit Formalism, Saarbrucken: LAMBERT Academic Publishing, 2015. [3] A. Soiguine, "Polarizations as States and Their Evolution in Geometric Algebra Terms with Variable Complex Plane," Journal of Applied Mathematics and Physics, vol. 6, no. 4, 2018. [4] A. Soiguine, Methods of Vector Algebra in Applied Problems, Leningrad: Naval Academy, 1990. [5] A. Soiguine, "The geometric algebra lift of qubits via basic solutions of Maxwell equation," 21 May 2018. [Online]. Available: https://arxiv.org/abs/1805.11953.
3
Obviously, the result qualitatively does not depend on extra state rotation caused by Clifford translation. The latter just increases the speed of rotation around vector dual to πΌπ .
6