Quantum converter and quantum conversion method

Abstract

This quantum converter comprises: a laminate that includes a topological insulator film and a ferromagnet film which are alternately laminated and that has an interface between the topological insulator film and the ferromagnet film; a magnetic field application unit that applies, to the laminate, a magnetic field which includes a component perpendicular to the interface; and a microwave transmission / reception unit that transmits and receives microwaves to and from the laminate. The interface of the laminate is irradiated with laser light. The quantum converter can be used in, for example, a quantum computer.

Description

Quantum converter and quantum conversion method

[0001] The present disclosure relates to quantum transducers and methods of quantum transformation.

[0002] Quantum computers can perform quantum conversion between microwave photons and optical photons, and quantum converters have been proposed for quantum conversion.

[0003] JP 2013-500530 A JP 2019-512104 A U.S. Patent Application Publication No. 2022 / 0215281

[0004] R. Hisatomi et al., Phys. Rev. B 93, 174427 (2016)Tse & MacDonald, Phys. Rev. Lett. 105 057401 (2010)J. Maciejko et al., Phys. Rev. Lett. 105 166803 (2010)

[0005] Conventional quantum converters have low conversion efficiency in quantum conversion.

[0006] An object of the present disclosure is to provide a quantum converter and a quantum conversion method that can improve conversion efficiency.

[0007] According to one aspect of the present disclosure, there is provided a quantum converter comprising: a stack including a topological insulator film and a ferromagnetic film stacked on top of each other, the stack having an interface between the topological insulator film and the ferromagnetic film; a magnetic field application unit that applies a magnetic field including a component perpendicular to the interface to the stack; and a microwave transceiver unit that transmits and receives microwaves to and from the stack; and the interface of the stack is irradiated with laser light.

[0008] According to the present disclosure, conversion efficiency can be improved.

[0009] FIG. 1 is a schematic diagram showing a quantum converter according to a first reference example. FIG. 2 is a schematic diagram showing a quantum converter according to a second reference example. FIG. 3 is a schematic diagram showing a quantum converter according to the first embodiment. FIG. 4 is a schematic diagram showing a quantum converter according to the second embodiment. FIG. 5 is a diagram showing the relationship between the thickness of a ferromagnetic film, the number of topological insulator films, and the ratio of conversion efficiencies. FIG. 6 is a schematic diagram showing a quantum converter according to a third embodiment. FIG. 7 is a schematic diagram showing a quantum converter according to a fourth embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description may be omitted.

[0011] (Reference Example) First, a first reference example will be described. Fig. 1 is a schematic diagram showing a quantum converter according to the first reference example.

[0012] As shown in FIG. 1, the quantum converter 100X according to the first reference example includes a microwave resonator 30, a laminate 10X, an S pole 51, an N pole 52, and an antenna 40.

[0013] The stack 10X includes a ferromagnetic topological insulator film 11X and a first film 12X. The ferromagnetic topological insulator film 11X has a first surface 11XA and a second surface 11XB opposite to the first surface 11XA. The first film 12X is in contact with the first surface 11XA. The first film 12X is made of, for example, a non-magnetic insulator. The first film 12X is made of, for example, SrTiO ３ , InP or Al ２ O ３ The ferromagnetic topological insulator film 11X includes a topological insulator and a ferromagnetic material doped in the topological insulator. For example, the topological insulator includes Bi, Sb, and Te, and the ferromagnetic material includes Cr or V, or both. The composition of the ferromagnetic topological insulator film 11X is, for example, Cr ｘ (Bi １－ｙ Sb ｙ ) ２－ｘ Te ３ , V ｘ (Bi１－ｙ Sb ｙ ) ２－ｘ Te ３ For example, the value of x is 0.1 or more and 0.6 or less, and the value of y is 0.7 or more and 0.9 or less. The thickness of the ferromagnetic topological insulator film 11X is, for example, 5 nm or more and 100 μm or less. The ferromagnetic topological insulator film 11X has a square planar shape with a side length of approximately 1 mm when viewed from a direction perpendicular to the first surface 11XA. The planar shape of the ferromagnetic topological insulator film 11X is not limited to a square shape, and may be a circular shape, etc.

[0014] The south pole 51 and the north pole 52 are provided on the outer wall surface of the microwave resonator 30. The south pole 51 faces the first surface 11XA, and the north pole 52 faces the second surface 11XB. A magnetic field H directed from the south pole 51 to the north pole 52 is generated between the south pole 51 and the north pole 52. The south pole 51 and the north pole 52 act as magnetic field application units and apply the magnetic field H, which includes a component perpendicular to the first surface 11XA, to the ferromagnetic topological insulator film 11X.

[0015] The antenna 40 is provided on the outer wall surface of the microwave resonator 30. The antenna 40 serves as a microwave transmitting / receiving unit, transmitting and receiving microwaves to and from the ferromagnetic topological insulator film 11X.

[0016] The microwave resonator 30 is provided with an inlet 31 and an outlet 32. The inlet 31 faces the first surface 11XA, and the outlet 32 ​​faces the second surface 11XB. An optical fiber is connected to the inlet 31, and laser light L1 is irradiated from the outside toward the ferromagnetic topological insulator film 11X through the inlet 31. The laser light L1 is irradiated onto the first surface 11XA of the ferromagnetic topological insulator film 11X. An optical fiber is connected to the outlet 32, and laser light L2 that has transmitted through the ferromagnetic topological insulator film 11X is extracted to the outside through the outlet 32. The laser light L1 is linearly polarized laser light.

[0017] The polarization and the like of the laser light L2 that is output to the outside through the output port 32 are detected. In this way, microwave photons of the microwaves that are irradiated onto the ferromagnetic topological insulator film 11X through the antenna 40 are quantum converted into optical photons.

[0018] Here, the characteristics of the ferromagnetic topological insulator film 11X will be described.

[0019] In general, the photon conversion efficiency η of a ferromagnetic material using the Faraday effect is approximately equal to "Aφ Ｆ ２ / N Ｓ " where "A" is a coefficient determined by the intensity of the laser light, and "φ Ｆ " is the Faraday rotation angle, and "N Ｓ " is the total number of spins contained in the ferromagnetic material. The value of A is, for example, 10 １０ That's about it.

[0020] In general, the Faraday rotation angle φ in a ferromagnetic topological insulator film Ｆ is "tan －１ α (rad)" where α is the fine structure constant and "tan －１ α (rad)” value, i.e., the Faraday rotation angle φ Ｆ is approximately 1 / 137 rad.

[0021] The total number of spins N contained in the ferromagnetic topological insulator film 11X Ｓ is the spin density per unit volume of the ferromagnetic topological insulator film 11X, Ｓ (mm －３ ), and the volume of the ferromagnetic topological insulator film 11X is V (mm ３ ) then "n Ｓ The spin density per unit volume of the ferromagnetic material contained in the ferromagnetic topological insulator film 11X is n Ｓ０ (mm －３ ), the atomic ratio of the ferromagnetic material in the ferromagnetic topological insulator film 11X is γ Ｓ Then, the spin density n per unit volume of the ferromagnetic topological insulator film 11X is Ｓ is "γ Ｓ ×n Ｓ０ (mm －３ )"

[0022] As an example, the composition is Cr ０．１５ (Bi ０．１ Sb ０．９ ) １．８５ Te ３The spin density n of the ferromagnetic topological insulator film 11X when (x=0.15, y=0.9) Ｓ can be calculated as follows: (Bi ０．１ Sb ０．９ ) ２ Te ３ In the case of Cr, 40 atomic % is Bi or Sb. ０．１５ (Bi ０．１ Sb ０．９ ) １．８５ Te ３ So, (Bi ０．１ Sb ０．９ ) ２ Te ３ 15 atomic % of Bi or Sb contained in is substituted with Cr. ０．１５ (Bi ０．１ Sb ０．９ ) １．８５ Te ３ The atomic percentage of Cr in the Cr layer is 6 atomic %. Therefore, the spin density per unit volume of Cr is n Ｓ０，Ｃｒ Then, the composition is Cr ０．１５ (Bi ０．１ Sb ０．９ ) １．８５ Te ３ The spin density n of the ferromagnetic topological insulator film 11X when Ｓ is "0.06 x n Ｓ０，Ｃｒ (mm －３ From the above, it can be seen that the composition is Cr ０．１５ (Bi ０．１ Sb ０．９ ) １．８５ Te ３ The conversion efficiency η of the ferromagnetic topological insulator film 11X when ＴＩＸ "A (1 / 137) ２ / (0.06 x n Ｓ０，Ｃｒ × V) The spin density n Ｓ０，Ｃｒ is assumed to be the same as the spin density of yttrium iron garnet (YIG), which is 2.1 × 10 １９ mm －３ Therefore, the thickness d of the ferromagnetic topological insulator film 11X is 30 nm, and the area S of the first surface 11XA is 1 mm ２ When , the conversion efficiency η of the ferromagnetic topological insulator film 11X is ＴＩＸis 1.4 x 10 －８ That's about it.

[0023] Next, a second reference example will be described for comparison with the first reference example. The second reference example differs from the first reference example mainly in the configuration of the ferromagnetic material and the arrangement of the magnetic poles. Figure 2 is a schematic diagram showing a quantum converter according to the second reference example.

[0024] As shown in Fig. 2, the quantum converter 100Y according to the second reference example has a ferromagnetic sphere 10Y instead of the stack 10X. The sphere 10Y is made of YIG and has a diameter of 0.75 mm. The south pole 51 and the north pole 52 are arranged so that a magnetic field H is formed in a direction perpendicular to the propagation direction of the laser light L1. The other configurations are the same as those of the first reference example.

[0025] Faraday rotation angle φ of sphere 10Y Ｆ is expressed as "γ × d (rad)" where γ is the Verdet constant (rad / mm) and d is the diameter (mm). The Verdet constant of YIG is 0.38 (rad / mm).

[0026] The total number of spins contained in the sphere 10Y is N Ｓ is the spin density per unit volume of the sphere 10Y, Ｓ (mm －３ , the volume of the sphere 10Y is V (mm ３ ) then "n Ｓ ×V". The entire sphere 10Y is made of YIG, which is a ferromagnetic material, and the spin density is n Ｓ is the spin density per unit volume of YIG, n Ｓ０ (mm －３ From the above, the spin density per unit volume of YIG is equal to n Ｓ０ to n Ｓ０，ＹＩＧ Then, the conversion efficiency η of the sphere 10Y made of YIG is ＹＩＧ is "A (0.38 x 0.75) ２ / (n Ｓ０，ＹＩＧ × V) The spin density n Ｓ０，ＹＩＧ is 2.1 x 10 １９ mm －３ Therefore, the volume V is 0.2209 mm ３ (diameter is 0.75 mm), the conversion efficiency η of the sphere 10YＹＩＧ is 3.0 x 10 －１０ That's about it.

[0027] Therefore, the conversion efficiency η of the ferromagnetic topological insulator film 11X in the first reference example ＴＩＸ is the conversion efficiency η of the sphere 10Y in the second reference example. ＹＩＧ 10 of ２ About twice as big.

[0028] However, the Curie point of a ferromagnetic topological insulator is about 1 K to 10 K, and the operating temperature of the first reference example is also about 1 K to 10 K. Therefore, the inventors of the present application conducted extensive research to improve the conversion efficiency η even at higher temperatures. As a result, they came up with the following embodiment.

[0029] First Embodiment Next, a first embodiment will be described. The first embodiment relates to a quantum converter. Fig. 3 is a schematic diagram showing a quantum converter according to the first embodiment.

[0030] 3 , the quantum converter 100 according to the first embodiment has, similarly to the first reference example, a microwave resonator 30, an S pole 51, an N pole 52, and an antenna 40. The quantum converter 100 has a stack 10 instead of the stack 10X in the first reference example, and further has a substrate 15.

[0031] The stack 10 includes a topological insulator film 11 and a ferromagnetic film 12 stacked on top of each other. The topological insulator film 11 and the ferromagnetic film 12 are in contact with each other, and the stack 10 has an interface 13 between the topological insulator film 11 and the ferromagnetic film 12.

[0032] The topological insulator film 11 includes a topological insulator. For example, the topological insulator film 11 includes Bi ２ Se ３ or (Bi ｘ Sb １－ｘ ) ２ Te ３ For example, the value of x is 0.7 or more and 0.9. The thickness of the topological insulator film 11 is, for example, 5 nm or more and 100 μm or less. The topological insulator film 11 is not doped with a ferromagnetic material and is a non-magnetic film.

[0033] The ferromagnetic film 12 is, for example, a ferromagnetic insulating film. The Curie point of the ferromagnetic film 12 is, for example, 100 K or higher, preferably 200 K or higher, more preferably 300 K or higher, and further preferably 400 K or higher. For example, the ferromagnetic film 12 is a Y ３ Fe ５ O １２ (YIG), Tm ３ Fe ５ O １２ (TIG), EuS, Cr ２ Ge ２ Te ６ , BaFe １２ O １９ The thickness of the ferromagnetic film 12 is, for example, 1 nm or more and 30 nm or less.

[0034] The substrate 15 is, for example, a non-magnetic substrate. ３ , InP or Al ２ O ３ or any combination thereof. ３ substrate, InP substrate or Al ２ O ３ The substrate 15 is fixed to the inside of the microwave resonator 30 by a support member 35.

[0035] The stack 10 is provided on a substrate 15. For example, the ferromagnetic film 12 is in contact with the substrate 15. The topological insulator film 11 and the ferromagnetic film 12 have a square planar shape with a side length of approximately 0.5 mm when viewed from a direction parallel to the stacking direction. The planar shapes of the topological insulator film 11 and the ferromagnetic film 12 are not limited to a square, and may be circular, etc.

[0036] As in the first reference example, the south pole 51 and the north pole 52 are provided on the outer wall surface of the microwave resonator 30. The south pole 51 faces the substrate 15, and the north pole 52 faces the topological insulator film 11. A magnetic field H directed from the south pole 51 to the north pole 52 is generated between the south pole 51 and the north pole 52. The south pole 51 and the north pole 52 act as magnetic field application units and apply the magnetic field H, which includes a component perpendicular to the interface 13, to the stack 10.

[0037] As in the first embodiment, the antenna 40 is provided on the outer wall surface of the microwave resonator 30. The antenna 40 serves as a microwave transmitting / receiving section and transmits and receives microwaves to and from the laminate 10.

[0038] As in the first reference example, the microwave resonator 30 is provided with an inlet 31 and an outlet 32. The inlet 31 faces the substrate 15, and the outlet 32 ​​faces the topological insulator film 11. An optical fiber is connected to the inlet 31, and laser light L1 is irradiated from the outside toward the stack 10 through the inlet 31. The laser light L1 is irradiated onto the interface 13 through the substrate 15 and the ferromagnetic film 12. An optical fiber is connected to the outlet 32, and laser light L2 that has passed through the stack 10 is extracted to the outside through the outlet 32. The laser light L1 is linearly polarized laser light. The ferromagnetic film 12 is made of a material that can transmit the laser light L1.

[0039] The polarization and the like of the laser light L2 is detected when it is output to the outside through the output port 32. In this way, the microwave photons of the microwaves irradiated onto the laminate 10 through the antenna 40 are quantum converted into optical photons.

[0040] Here, the characteristics of the laminate 10 will be described.

[0041] As described above, the photon conversion efficiency η of a ferromagnetic material utilizing the Faraday effect is approximately Ｆ ２ / N Ｓ In general, the Faraday rotation angle φ in a stack of a topological insulator film and a ferromagnetic film is expressed as Ｆ Also "tan －１ α (rad)" and the Faraday rotation angle φ Ｆ is approximately 1 / 137 rad.

[0042] The total number of spins contained in the stack 10, N Ｓ is the spin density per unit volume of the ferromagnetic film 12, Ｓ (mm －３ ), the volume of the ferromagnetic film 12 is V (mm ３ ) then "n Ｓ ×V".

[0043] The conversion efficiency η of the laminate 10 when the entire ferromagnetic film 12 is made of YIG is ＴＩ "A (1 / 137) ２ / (n Ｓ０，ＹＩＧ × V) The spin density n Ｓ０，ＹＩＧ is 2.1 x 10 １９ mm －３ Therefore, the thickness d of the ferromagnetic film 12 is 1 nm, and the area S of the interface 13 is 0.25 mm ２ When this is the case, the conversion efficiency η of the stack 10 ＴＩ is 1.0 x 10 －７ That's about it.

[0044] Therefore, the conversion efficiency η of the stack 10 in the first embodiment ＴＩ is the conversion efficiency η of the sphere 10Y in the second reference example. ＹＩＧ 3 x 10 ２ About twice as big.

[0045] Furthermore, in the stack 10, exchange interaction occurs between electrons on the surface of the topological insulator film 11 and the ferromagnetic material of the ferromagnetic film 12 even at temperatures higher than 10 K. Therefore, unlike the ferromagnetic topological insulator film 11X in the first reference example, the Faraday effect can be obtained even at temperatures higher than 10 K, for example, at temperatures of around 100 K, and the conversion efficiency η can be improved.

[0046] If the thickness d of the topological insulator film 11 is less than 5 nm, the topological insulator film 11 behaves as a two-dimensional material, which may make it difficult to obtain the Faraday effect. Furthermore, if the thickness d is 5 nm or greater, the topological insulator film 11 can be stably formed. The topological insulator film 11 can be formed by, for example, molecular beam epitaxy (MBE).

[0047] Furthermore, if the thickness of the ferromagnetic film 12 is less than 1 nm, ferromagnetic resonance may not occur. If the thickness is 1 nm or more, the ferromagnetic film 12 can be easily and stably formed. The ferromagnetic film 12 can be formed by, for example, pulsed laser deposition.

[0048] Second Embodiment A second embodiment will be described. The second embodiment differs from the first embodiment mainly in the configuration of the stack. Fig. 4 is a schematic diagram showing a quantum converter according to the second embodiment.

[0049] As shown in FIG. 4, a quantum converter 200 according to the second embodiment has a stack 20 instead of the stack 10 .

[0050] The stack 20 includes a plurality of topological insulator films 11 and a plurality of ferromagnetic films 12 stacked on top of each other. The topological insulator films 11 and the ferromagnetic films 12 are stacked alternately. The stack 20 has a plurality of interfaces 13.

[0051] Other configurations of the second embodiment are similar to those of the first embodiment.

[0052] According to the second embodiment, a high conversion efficiency can be obtained, similar to the first embodiment. In addition, in the second embodiment, since the stack 10 includes a plurality of topological insulator films 11 and a plurality of interfaces 13, a higher conversion efficiency η ＴＩ For example, when the number of topological insulator films 11 is 30, the conversion efficiency η of the stack 20 in the second embodiment is ＴＩ is the conversion efficiency η of the sphere 10Y in the second reference example. ＹＩＧ 10 of ４ About twice as big.

[0053] Next, the thickness d of the ferromagnetic film 12 and the number N of the topological insulator films 11 are Ｌ and the ratio of conversion efficiencies (η ＴＩ / η ＹＩＧ 5 shows the relationship between the thickness d of the ferromagnetic film 12 and the number N of the topological insulator films 11. Ｌ and the ratio of conversion efficiencies (η ＴＩ / η ＹＩＧ 5, the number N of topological insulator films 11 is Ｌ If the thickness d of the topological insulator film 11 is constant, the ratio of the conversion efficiencies (η ＴＩ / η ＹＩＧ ) becomes larger. In addition, if the thickness d of the topological insulator film 11 is constant, the number N of the topological insulator films 11 becomes larger. ＬThe larger the conversion efficiency ratio (η ＴＩ / η ＹＩＧ The thickness of the ferromagnetic film 12 is preferably 1 nm or more and 20 nm or less.

[0054] Third Embodiment A third embodiment will be described. The third embodiment differs from the second embodiment mainly in the configuration of the stack. Fig. 6 is a schematic diagram showing a quantum converter according to the third embodiment.

[0055] As shown in FIG. 6, a quantum converter 300 according to the third embodiment has a stack 21 instead of the stack 20 .

[0056] The stack 21 includes a plurality of topological insulator films 11, a plurality of ferromagnetic films 12, and a plurality of non-magnetic spacers 14 stacked on top of each other. The topological insulator films 11 and the spacers 14 are alternately stacked, and the ferromagnetic films 12 are disposed between the topological insulator films 11 and the spacers 14. The spacers 14 may be made of, for example, Si or SrTiO ３ , InP or Al ２ O ３ or any combination thereof. ３ film, InP film or Al ２ O ３ It may also be a membrane.

[0057] The distance between two adjacent topological insulator films 11 in the stacking direction is, for example, 5 nm or more. The thickness of the spacer 14 is, for example, 3 nm or more. If the thickness of the spacer 14 is 3 nm or more and the thickness of the ferromagnetic film 12 is 1 nm or more, the distance between two adjacent topological insulator films 11 in the stacking direction is 5 nm or more. If the distance between two adjacent topological insulator films 11 in the stacking direction is less than 5 nm, hybridization of the surface state between these two topological insulator films 11 may occur. If the distance between two adjacent topological insulator films 11 in the stacking direction is 5 nm or more, this hybridization can be suppressed.

[0058] (Fourth Embodiment) A fourth embodiment will be described. The fourth embodiment differs from the second embodiment mainly in the polarization of the laser light irradiated onto the stack. Fig. 7 is a schematic diagram showing a quantum converter according to the fourth embodiment.

[0059] 7 , in the quantum converter 400 according to the fourth embodiment, laser light L3 is irradiated from the outside toward the stack 20 through the inlet 31. The laser light L3 includes two types of laser light whose deflection angles are orthogonal to each other. The laser light L3 is irradiated onto the first surface of the stack 20. The outlet 32 ​​does not necessarily have to be provided.

[0060] In the fourth embodiment, microwaves corresponding to the polarization of the laser light L3 are emitted from the laminate 20 and output to the outside through the antenna 40. In this way, the optical photons of the laser light L3 irradiated onto the laminate 10 are quantum converted into microwave photons of the microwaves.

[0061] Similarly to the second embodiment, the fourth embodiment can also achieve high conversion efficiency.

[0062] In the fourth embodiment, the laminate 10 or 21 may be used instead of the laminate 20 .

[0063] The quantum converter according to the present disclosure can be used, for example, for communication between superconducting qubits housed in a plurality of refrigerators. However, the use of the quantum converter according to the present disclosure is not limited to communication between superconducting qubits. The quantum converter can also be used for quantum computing.

[0064] Although the preferred embodiments have been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0065] 10, 20, 21: Stacked body 11: Topological insulator film 12: Ferromagnetic film 13: Interface 14: Spacer 15: Substrate 30: Microwave resonator 31: Inlet 32: Outlet 40: Antenna 51: South pole 52: North pole 100, 200, 300, 400: Quantum converter

Claims

1. A laminate comprising a topological insulating film and a ferromagnetic film stacked on top of each other, and having an interface between the topological insulating film and the ferromagnetic film, A magnetic field application unit that applies a magnetic field containing a component perpendicular to the interface to the laminate, A microwave transmitting and receiving unit that transmits and receives microwaves with the laminate, It has, A quantum converter characterized in that laser light is irradiated onto the interface of the laminate.

2. It has a microwave resonator, The quantum converter according to claim 1, characterized in that the laminate is provided within the microwave resonator.

3. The quantum converter in the microwave resonator is provided with an inlet for introducing the laser light from the outside.

4. The quantum converter according to claim 3, characterized in that the microwave resonator has an outlet formed therein through which the laser light that has passed through the laminate is led out to the outside.

5. The quantum converter according to any one of claims 1 to 4, characterized in that the ferromagnetic film is a ferromagnetic insulating film.

6. The quantum converter according to any one of claims 1 to 4, characterized in that the thickness of the topological insulator film is 5 nm or more and 100 μm or less.

7. The quantum converter according to any one of claims 1 to 4, characterized in that the thickness of the ferromagnetic film is 1 nm or more and 30 nm or less.

8. The quantum converter according to any one of claims 1 to 4, characterized in that the laminate has a non-magnetic spacer between two adjacent topological insulating films in the stacking direction.

9. The laminate comprises a plurality of the topological insulating film and the ferromagnetic film, The quantum converter according to any one of claims 1 to 4, characterized in that the distance between two adjacent topological insulator films in the stacking direction is 5 nm or more.

10. A laminate comprising a topological insulating film and a ferromagnetic film stacked on top of each other, and having an interface between the topological insulating film and the ferromagnetic film, A magnetic field application unit that applies a magnetic field containing a component perpendicular to the interface to the laminate, A microwave transmitting and receiving unit that transmits and receives microwaves with the laminate, A quantum transformation method using a quantum converter having, A quantum transformation method characterized by comprising the step of irradiating the interface of the laminate with laser light.