numerical renormalization group computation of magnetic relaxation rates

31
Numerical Renormalization-Group computation of magnetic relaxation rates Krissia de Zawadzki, Luiz Nunes de Oliveira, Jos´ e Wilson M. Pinto Instituto de F´ ısica de S˜ ao Carlos - Universidade de S˜ ao Paulo Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 1 / 11

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We report an essentially exact numerical renormalization-group (NRG) computation of the temperature-dependent NMR rate $1/T_1$ of a probe at a distance $R$ from a magnetic impurity in a metallic host. We split the metallic states into two subsets, A and B. The former comprises electrons $a_k$ in $s$-wave states about the magnetic-impurity site. The coupling between the $a_k$ band and the impurity is described by the Anderson Hamiltonian, diagonalizable by the NRG procedure. Each state $b_k$ in the B subset is a linear combination of an $s$-wave state about the probe site with the degenerate $a_k$, constructed to be orthogonal to all the $a_k$'s. The $b_k$ band hence decouples from the impurity and is analytically treatable. We show that the relaxation rate has three components: (i) a constant associated with the $b_k$'s; (ii) a $T$-dependent term associated with the $a_k$'s, which decays in proportion to $1/(k_FR)^2$, where $k_F$ is the Fermi momentum; and (iii) another $T$-dependent term due to the interference between the $a_k$'s and the $b_k$'s. The interference term shows Friedel oscillations whose amplitude, proportional to $1/k_FR$, can be mapped onto the universal function of $T/T_K$ describing the Kondo resistivity. We compare our findings with results in the literature.

TRANSCRIPT

Page 1: Numerical Renormalization Group computation of magnetic relaxation rates

Numerical Renormalization-Group computationof magnetic relaxation rates

Krissia de Zawadzki, Luiz Nunes de Oliveira, Jose Wilson M. Pinto

Instituto de FΔ±sica de Sao Carlos - Universidade de Sao Paulo

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 1 / 11

Page 2: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Radius of Kondo screening cloud

Radius of Kondo screening cloud

π‘…π‘˜

𝑅𝐾 ∝ π‘‡βˆ’1𝐾

General consensus

𝑅𝐾 = ~𝑣𝐹 /π‘˜π΅π‘‡πΎ

Boyce &Slichter

NMR:

Experimental arrangement:

NMR probe: 𝑅 from the impurity

NRG computation of the spin

lattice relaxation rate 1/(𝑇1𝑇 ) as

function of 𝑇 and 𝑅

Can we measure 𝑅𝐾 via NMR?

Our findings:

Yes, we can!

T dependence changes as probe

crosses 𝑅𝐾

Phase of low-𝑇 Friedel oscillations

also changes

LASZLO, B. PRB, 75 (2007). BOYCE, J.B; SLICHTER, C.P. PRL, 32, 61 (1974).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 2 / 11

Page 3: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Radius of Kondo screening cloud

Radius of Kondo screening cloud

π‘…π‘˜

𝑅𝐾 ∝ π‘‡βˆ’1𝐾

General consensus

𝑅𝐾 = ~𝑣𝐹 /π‘˜π΅π‘‡πΎ

Boyce &Slichter

NMR:

Experimental arrangement:

NMR probe: 𝑅 from the impurity

NRG computation of the spin

lattice relaxation rate 1/(𝑇1𝑇 ) as

function of 𝑇 and 𝑅

Can we measure 𝑅𝐾 via NMR?

Our findings:

Yes, we can!

T dependence changes as probe

crosses 𝑅𝐾

Phase of low-𝑇 Friedel oscillations

also changes

LASZLO, B. PRB, 75 (2007). BOYCE, J.B; SLICHTER, C.P. PRL, 32, 61 (1974).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 2 / 11

Page 4: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Radius of Kondo screening cloud

Radius of Kondo screening cloud

π‘…π‘˜

𝑅𝐾 ∝ π‘‡βˆ’1𝐾

General consensus

𝑅𝐾 = ~𝑣𝐹 /π‘˜π΅π‘‡πΎ

Boyce &Slichter

NMR:

Experimental arrangement:

NMR probe: 𝑅 from the impurity

NRG computation of the spin

lattice relaxation rate 1/(𝑇1𝑇 ) as

function of 𝑇 and 𝑅

Can we measure 𝑅𝐾 via NMR?

Our findings:

Yes, we can!

T dependence changes as probe

crosses 𝑅𝐾

Phase of low-𝑇 Friedel oscillations

also changes

LASZLO, B. PRB, 75 (2007). BOYCE, J.B; SLICHTER, C.P. PRL, 32, 61 (1974).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 2 / 11

Page 5: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Radius of Kondo screening cloud

Radius of Kondo screening cloud

π‘…π‘˜

𝑅𝐾 ∝ π‘‡βˆ’1𝐾

General consensus

𝑅𝐾 = ~𝑣𝐹 /π‘˜π΅π‘‡πΎ

Boyce &Slichter

NMR:

Experimental arrangement:

NMR probe: 𝑅 from the impurity

NRG computation of the spin

lattice relaxation rate 1/(𝑇1𝑇 ) as

function of 𝑇 and 𝑅

Can we measure 𝑅𝐾 via NMR?

Our findings:

Yes, we can!

T dependence changes as probe

crosses 𝑅𝐾

Phase of low-𝑇 Friedel oscillations

also changes

LASZLO, B. PRB, 75 (2007). BOYCE, J.B; SLICHTER, C.P. PRL, 32, 61 (1974).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 2 / 11

Page 6: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Radius of Kondo screening cloud

Radius of Kondo screening cloud

π‘…π‘˜

𝑅𝐾 ∝ π‘‡βˆ’1𝐾

General consensus

𝑅𝐾 = ~𝑣𝐹 /π‘˜π΅π‘‡πΎ

Boyce &Slichter

NMR:

Experimental arrangement:

NMR probe: 𝑅 from the impurity

NRG computation of the spin

lattice relaxation rate 1/(𝑇1𝑇 ) as

function of 𝑇 and 𝑅

Can we measure 𝑅𝐾 via NMR?

Our findings:

Yes, we can!

T dependence changes as probe

crosses 𝑅𝐾

Phase of low-𝑇 Friedel oscillations

also changes

LASZLO, B. PRB, 75 (2007). BOYCE, J.B; SLICHTER, C.P. PRL, 32, 61 (1974).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 2 / 11

Page 7: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

The quantum system

NRG Probe

Single-impurity Anderson model

𝐻 =

π»π‘π‘œπ‘›π‘‘βž ⏟ βˆ‘k

πœ€k𝑐†k𝑐k

+

π»π‘‘βž ⏟ πœ€π‘‘π‘

†𝑑𝑐𝑑 + π‘ˆπ‘›π‘‘β†‘π‘›π‘‘β†“ +

π»π‘–π‘›π‘‘βž ⏟ βˆšΞ“

πœ‹(𝑓†

0𝑐𝑑 +𝐻.𝑐.)

πœ€ = 𝑣𝐹𝐷

(π‘˜ βˆ’ π‘˜πΉ )

+𝐷

βˆ’π·

π‘˜πΉ

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄[Ψ†

↑(οΏ½οΏ½)Ψ↓(οΏ½οΏ½)πΌβˆ’ +𝐻.𝑐.]

Ξ¨πœ‡ =βˆ‘k

𝑒𝑖k.R𝑐k

1

𝑇1=

4πœ‹

~

βˆ‘πΌ,𝐹

π‘’βˆ’π›½πΈπΌ |⟨𝐼|π»π‘π‘Ÿπ‘œπ‘π‘’|𝐹 ⟩|2𝛿(𝐸𝐼 βˆ’ 𝐸𝐹 )

𝑓0 =1√𝜌

βˆ‘k

𝑐k

𝑅

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 3 / 11

Page 8: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

The quantum system

NRG Probe

Single-impurity Anderson model

𝐻 =

π»π‘π‘œπ‘›π‘‘βž ⏟ βˆ‘k

πœ€k𝑐†k𝑐k +

π»π‘‘βž ⏟ πœ€π‘‘π‘

†𝑑𝑐𝑑 + π‘ˆπ‘›π‘‘β†‘π‘›π‘‘β†“

+

π»π‘–π‘›π‘‘βž ⏟ βˆšΞ“

πœ‹(𝑓†

0𝑐𝑑 +𝐻.𝑐.)

πœ€ = 𝑣𝐹𝐷

(π‘˜ βˆ’ π‘˜πΉ )

+𝐷

βˆ’π·

π‘˜πΉ

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄[Ψ†

↑(οΏ½οΏ½)Ψ↓(οΏ½οΏ½)πΌβˆ’ +𝐻.𝑐.]

Ξ¨πœ‡ =βˆ‘k

𝑒𝑖k.R𝑐k

1

𝑇1=

4πœ‹

~

βˆ‘πΌ,𝐹

π‘’βˆ’π›½πΈπΌ |⟨𝐼|π»π‘π‘Ÿπ‘œπ‘π‘’|𝐹 ⟩|2𝛿(𝐸𝐼 βˆ’ 𝐸𝐹 )

𝑓0 =1√𝜌

βˆ‘k

𝑐k

𝑅

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 3 / 11

Page 9: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

The quantum system

NRG Probe

Single-impurity Anderson model

𝐻 =

π»π‘π‘œπ‘›π‘‘βž ⏟ βˆ‘k

πœ€k𝑐†k𝑐k +

π»π‘‘βž ⏟ πœ€π‘‘π‘

†𝑑𝑐𝑑 + π‘ˆπ‘›π‘‘β†‘π‘›π‘‘β†“ +

π»π‘–π‘›π‘‘βž ⏟ βˆšΞ“

πœ‹(𝑓†

0𝑐𝑑 +𝐻.𝑐.)

πœ€ = 𝑣𝐹𝐷

(π‘˜ βˆ’ π‘˜πΉ )

+𝐷

βˆ’π·

π‘˜πΉ

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄[Ψ†

↑(οΏ½οΏ½)Ψ↓(οΏ½οΏ½)πΌβˆ’ +𝐻.𝑐.]

Ξ¨πœ‡ =βˆ‘k

𝑒𝑖k.R𝑐k

1

𝑇1=

4πœ‹

~

βˆ‘πΌ,𝐹

π‘’βˆ’π›½πΈπΌ |⟨𝐼|π»π‘π‘Ÿπ‘œπ‘π‘’|𝐹 ⟩|2𝛿(𝐸𝐼 βˆ’ 𝐸𝐹 )

𝑓0 =1√𝜌

βˆ‘k

𝑐k

𝑅

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 3 / 11

Page 10: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

The quantum system

NRG Probe

Single-impurity Anderson model

𝐻 =

π»π‘π‘œπ‘›π‘‘βž ⏟ βˆ‘k

πœ€k𝑐†k𝑐k +

π»π‘‘βž ⏟ πœ€π‘‘π‘

†𝑑𝑐𝑑 + π‘ˆπ‘›π‘‘β†‘π‘›π‘‘β†“ +

π»π‘–π‘›π‘‘βž ⏟ βˆšΞ“

πœ‹(𝑓†

0𝑐𝑑 +𝐻.𝑐.)

πœ€ = 𝑣𝐹𝐷

(π‘˜ βˆ’ π‘˜πΉ )

+𝐷

βˆ’π·

π‘˜πΉ

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄[Ψ†

↑(οΏ½οΏ½)Ψ↓(οΏ½οΏ½)πΌβˆ’ +𝐻.𝑐.]

Ξ¨πœ‡ =βˆ‘k

𝑒𝑖k.R𝑐k

1

𝑇1=

4πœ‹

~

βˆ‘πΌ,𝐹

π‘’βˆ’π›½πΈπΌ |⟨𝐼|π»π‘π‘Ÿπ‘œπ‘π‘’|𝐹 ⟩|2𝛿(𝐸𝐼 βˆ’ 𝐸𝐹 )

𝑓0 =1√𝜌

βˆ‘k

𝑐k

𝑅

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 3 / 11

Page 11: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Two-center basis

Two-center basis

Spherically symmetric operators

π‘πœ€ =βˆ‘k

𝑐 k 𝛿(πœ€βˆ’ πœ€k) (around impurity)

π‘‘πœ€ =βˆ‘k

𝑐 k 𝑒𝑖k.R𝛿(πœ€βˆ’ πœ€k) (around probe)

𝑐 πœ€

𝑑 πœ€

NRG

analytical

{π‘β€ πœ€, π‘‘πœ€β€²} = sin(π‘˜π‘…)π‘˜π‘… 𝛿(πœ€βˆ’ πœ€β€²)

Gram-Schmidt construction

π‘πœ€πœ‡ = 1√1βˆ’π‘Š 2

(π‘‘πœ€πœ‡ βˆ’π‘Šπ‘πœ€πœ‡)

π‘Š = π‘Š (πœ€,𝑅) = sin(π‘˜π‘…)π‘˜π‘…

π‘˜π‘… = π‘˜πΉπ‘…(1 + πœ€

𝐷

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 4 / 11

Page 12: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Two-center basis

Two-center basis

Spherically symmetric operators

π‘πœ€ =βˆ‘k

𝑐 k 𝛿(πœ€βˆ’ πœ€k) (around impurity)

π‘‘πœ€ =βˆ‘k

𝑐 k 𝑒𝑖k.R𝛿(πœ€βˆ’ πœ€k) (around probe)

𝑐 πœ€

𝑑 πœ€

NRG

analytical

{π‘β€ πœ€, π‘‘πœ€β€²} = sin(π‘˜π‘…)π‘˜π‘… 𝛿(πœ€βˆ’ πœ€β€²)

Gram-Schmidt construction

π‘πœ€πœ‡ = 1√1βˆ’π‘Š 2

(π‘‘πœ€πœ‡ βˆ’π‘Šπ‘πœ€πœ‡)

π‘Š = π‘Š (πœ€,𝑅) = sin(π‘˜π‘…)π‘˜π‘…

π‘˜π‘… = π‘˜πΉπ‘…(1 + πœ€

𝐷

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 4 / 11

Page 13: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Two-center basis

Two-center basis

Spherically symmetric operators

π‘πœ€ =βˆ‘k

𝑐 k 𝛿(πœ€βˆ’ πœ€k) (around impurity)

π‘‘πœ€ =βˆ‘k

𝑐 k 𝑒𝑖k.R𝛿(πœ€βˆ’ πœ€k) (around probe)

𝑐 πœ€

𝑑 πœ€

NRG

analytical

{π‘β€ πœ€, π‘‘πœ€β€²} = sin(π‘˜π‘…)π‘˜π‘… 𝛿(πœ€βˆ’ πœ€β€²)

Gram-Schmidt construction

π‘πœ€πœ‡ = 1√1βˆ’π‘Š 2

(π‘‘πœ€πœ‡ βˆ’π‘Šπ‘πœ€πœ‡)

π‘Š = π‘Š (πœ€,𝑅) = sin(π‘˜π‘…)π‘˜π‘…

π‘˜π‘… = π‘˜πΉπ‘…(1 + πœ€

𝐷

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 4 / 11

Page 14: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

NRG and Lanczos basis

NRG and Lanczos basis

𝐻𝑁 =1

π’Ÿπ‘

(π‘βˆ’1βˆ‘π‘›=0

𝑑𝑛(𝑓†𝑛𝑓𝑛+1 +𝐻.𝑐.) +

βˆšΞ“

πœ‹(𝑐†𝑑𝑓0 +𝐻.𝑐.) +𝐻𝑑

)NRG[4]

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄ [ πœ™β€ β†‘πœ™β†“ +Φ†

↑Φ↓ + (πœ™β€ β†‘Ξ¦β†“ +Φ†

β†‘πœ™β†“) ] Iβˆ’ +𝐻.𝑐.

πœ™πœ‡(𝑅) β‰‘βˆ« 𝐷

βˆ’π·

π‘‘πœ€βˆš

1 βˆ’ π‘Š (πœ€,𝑅)π‘πœ€πœ‡ Ξ¦πœ‡(𝑅) β‰‘βˆ‘π‘›

𝛾𝑛𝑓𝑛

analytically

numerically

1

𝑇1=

(1

𝑇1

)πœ™πœ™βŸ ⏞

1βˆ’π‘Š 2𝐹

+

(1

𝑇1

)ΦΦ⏟ ⏞

π‘Š 2𝐹

+

(1

𝑇1

)Ξ¦πœ™βŸ ⏞

(1βˆ’π‘ŠπΉ )π‘ŠπΉ

cte

π‘˜πΉπ‘…β‰ͺ

1

π‘˜πΉπ‘…

≫1

DULL

SMALL

π‘ŠπΉ =sin(π‘˜πΉπ‘…)

π‘˜πΉπ‘…

WILSON, K. Rev Mod Phys, 47, 773 (1975).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 5 / 11

Page 15: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

NRG and Lanczos basis

NRG and Lanczos basis

𝐻𝑁 =1

π’Ÿπ‘

(π‘βˆ’1βˆ‘π‘›=0

𝑑𝑛(𝑓†𝑛𝑓𝑛+1 +𝐻.𝑐.) +

βˆšΞ“

πœ‹(𝑐†𝑑𝑓0 +𝐻.𝑐.) +𝐻𝑑

)NRG[4]

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄ [ πœ™β€ β†‘πœ™β†“ +Φ†

↑Φ↓ + (πœ™β€ β†‘Ξ¦β†“ +Φ†

β†‘πœ™β†“) ] Iβˆ’ +𝐻.𝑐.

πœ™πœ‡(𝑅) β‰‘βˆ« 𝐷

βˆ’π·

π‘‘πœ€βˆš

1 βˆ’ π‘Š (πœ€,𝑅)π‘πœ€πœ‡ Ξ¦πœ‡(𝑅) β‰‘βˆ‘π‘›

𝛾𝑛𝑓𝑛

analytically

numerically

1

𝑇1=

(1

𝑇1

)πœ™πœ™βŸ ⏞

1βˆ’π‘Š 2𝐹

+

(1

𝑇1

)ΦΦ⏟ ⏞

π‘Š 2𝐹

+

(1

𝑇1

)Ξ¦πœ™βŸ ⏞

(1βˆ’π‘ŠπΉ )π‘ŠπΉ

cte

π‘˜πΉπ‘…β‰ͺ

1

π‘˜πΉπ‘…

≫1

DULL

SMALL

π‘ŠπΉ =sin(π‘˜πΉπ‘…)

π‘˜πΉπ‘…

WILSON, K. Rev Mod Phys, 47, 773 (1975).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 5 / 11

Page 16: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

NRG and Lanczos basis

NRG and Lanczos basis

𝐻𝑁 =1

π’Ÿπ‘

(π‘βˆ’1βˆ‘π‘›=0

𝑑𝑛(𝑓†𝑛𝑓𝑛+1 +𝐻.𝑐.) +

βˆšΞ“

πœ‹(𝑐†𝑑𝑓0 +𝐻.𝑐.) +𝐻𝑑

)NRG[4]

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄ [ πœ™β€ β†‘πœ™β†“ +Φ†

↑Φ↓ + (πœ™β€ β†‘Ξ¦β†“ +Φ†

β†‘πœ™β†“) ] Iβˆ’ +𝐻.𝑐.

πœ™πœ‡(𝑅) β‰‘βˆ« 𝐷

βˆ’π·

π‘‘πœ€βˆš

1 βˆ’ π‘Š (πœ€,𝑅)π‘πœ€πœ‡ Ξ¦πœ‡(𝑅) β‰‘βˆ‘π‘›

𝛾𝑛𝑓𝑛

analytically

numerically

1

𝑇1=

(1

𝑇1

)πœ™πœ™βŸ ⏞

1βˆ’π‘Š 2𝐹

+

(1

𝑇1

)ΦΦ⏟ ⏞

π‘Š 2𝐹

+

(1

𝑇1

)Ξ¦πœ™βŸ ⏞

(1βˆ’π‘ŠπΉ )π‘ŠπΉ

cte

π‘˜πΉπ‘…β‰ͺ

1

π‘˜πΉπ‘…

≫1

DULL

SMALL

π‘ŠπΉ =sin(π‘˜πΉπ‘…)

π‘˜πΉπ‘…

WILSON, K. Rev Mod Phys, 47, 773 (1975).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 5 / 11

Page 17: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

NRG and Lanczos basis

NRG and Lanczos basis

𝐻𝑁 =1

π’Ÿπ‘

(π‘βˆ’1βˆ‘π‘›=0

𝑑𝑛(𝑓†𝑛𝑓𝑛+1 +𝐻.𝑐.) +

βˆšΞ“

πœ‹(𝑐†𝑑𝑓0 +𝐻.𝑐.) +𝐻𝑑

)NRG[4]

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄ [ πœ™β€ β†‘πœ™β†“ +Φ†

↑Φ↓ + (πœ™β€ β†‘Ξ¦β†“ +Φ†

β†‘πœ™β†“) ] Iβˆ’ +𝐻.𝑐.

πœ™πœ‡(𝑅) β‰‘βˆ« 𝐷

βˆ’π·

π‘‘πœ€βˆš

1 βˆ’ π‘Š (πœ€,𝑅)π‘πœ€πœ‡ Ξ¦πœ‡(𝑅) β‰‘βˆ‘π‘›

𝛾𝑛𝑓𝑛

analytically

numerically

1

𝑇1=

(1

𝑇1

)πœ™πœ™βŸ ⏞

1βˆ’π‘Š 2𝐹

+

(1

𝑇1

)ΦΦ⏟ ⏞

π‘Š 2𝐹

+

(1

𝑇1

)Ξ¦πœ™βŸ ⏞

(1βˆ’π‘ŠπΉ )π‘ŠπΉ

cte

π‘˜πΉπ‘…β‰ͺ

1

π‘˜πΉπ‘…

≫1

DULL

SMALL

π‘ŠπΉ =sin(π‘˜πΉπ‘…)

π‘˜πΉπ‘…

WILSON, K. Rev Mod Phys, 47, 773 (1975).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 5 / 11

Page 18: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

NRG and Lanczos basis

NRG and Lanczos basis

𝐻𝑁 =1

π’Ÿπ‘

(π‘βˆ’1βˆ‘π‘›=0

𝑑𝑛(𝑓†𝑛𝑓𝑛+1 +𝐻.𝑐.) +

βˆšΞ“

πœ‹(𝑐†𝑑𝑓0 +𝐻.𝑐.) +𝐻𝑑

)NRG[4]

π»π‘π‘Ÿπ‘œπ‘π‘’ = βˆ’π΄ [ πœ™β€ β†‘πœ™β†“ +Φ†

↑Φ↓ + (πœ™β€ β†‘Ξ¦β†“ +Φ†

β†‘πœ™β†“) ] Iβˆ’ +𝐻.𝑐.

πœ™πœ‡(𝑅) β‰‘βˆ« 𝐷

βˆ’π·

π‘‘πœ€βˆš

1 βˆ’ π‘Š (πœ€,𝑅)π‘πœ€πœ‡ Ξ¦πœ‡(𝑅) β‰‘βˆ‘π‘›

𝛾𝑛𝑓𝑛

analytically

numerically

1

𝑇1=

(1

𝑇1

)πœ™πœ™βŸ ⏞

1βˆ’π‘Š 2𝐹

+

(1

𝑇1

)ΦΦ⏟ ⏞

π‘Š 2𝐹

+

(1

𝑇1

)Ξ¦πœ™βŸ ⏞

(1βˆ’π‘ŠπΉ )π‘ŠπΉ

cte

π‘˜πΉπ‘…β‰ͺ

1

π‘˜πΉπ‘…

≫1

DULL

SMALL

π‘ŠπΉ =sin(π‘˜πΉπ‘…)

π‘˜πΉπ‘…

WILSON, K. Rev Mod Phys, 47, 773 (1975).

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 5 / 11

Page 19: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Friedel oscillations

Friedel oscillations

9.8 10.0 10.2 10.4 10.6 10.8 11.0 11.2kFRΟ€

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

10.5Ο€

10Ο€ 10.25Ο€

T=1.7569eβˆ’4

T=9.8711eβˆ’8

10.0 10.5 11.0

0.16

0.17

1T

1T(kFR

)2

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 6 / 11

Page 20: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Relaxation rate - temperature dependence

π‘˜π΅π‘‡πΎ = 1.25Γ— 10βˆ’5

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1

kB T

0

1

2

3

4

5

6

7

(101+0.25)Ο€

(102+0.25)Ο€

(103+0.25)Ο€

(104+0.25)Ο€

(105+0.25)Ο€

(106+0.25)Ο€

(107+0.25)Ο€

(kFR

)2

kBT

( 1 T1

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 7 / 11

Page 21: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Interference relaxation rate

Interference relaxation rate

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-20

1

2

3

4

5

6

7

Rβ‰ˆRK

outside

inside

(kFR

)2

kBT

( 1 T1

)

kB T

kFR=(n+14)Ο€

Ξ»B =2Ο€vFkB T

de Broglie

n=102

n=105

n=107

n=102

n=105

n=107

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 8 / 11

Page 22: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Friedel oscillations

Friedel oscillations

101 102 103 104 105 106 107 108

kFRΟ€

1.58

1.60

1.62

1.64

1.66

1.68

1.70

1.72

RK β†’TK =1.25eβˆ’05

nΟ€

(n+1/2)Ο€

104 105 106

0.00010

0.00015

+1.6131

1T

1T(kFR

)2

Tβ‰ˆ5.62eβˆ’11

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 9 / 11

Page 23: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Conclusions

NMR to measure 𝑅𝐾 : OK!

Inside cloud, 𝑇 -dependent rate follows universal curve

Outside cloud, rate follows different curve

Phase of Friedel oscillations reverses around 𝑅 = 𝑅𝐾

Future prospects:

Other geometries

P-h symmetric case differs from assymetric ?

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 10 / 11

Page 24: Numerical Renormalization Group computation of magnetic relaxation rates

Introduction NRG calculations Numerical results Conclusions Acknowledgment

Acknowledgment

Thank you!

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 11 / 11

Page 25: Numerical Renormalization Group computation of magnetic relaxation rates

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 1 / 4

Page 26: Numerical Renormalization Group computation of magnetic relaxation rates

Additional results

Relaxation rate - 𝒒𝑠𝑖𝑑𝑒(𝑇 ) profile

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1

kB T

0

1

2

3

4

5

6

7

(101+0.5)Ο€

(102+0.5)Ο€

(103+0.5)Ο€

(104+0.5)Ο€

(105+0.5)Ο€

(106+0.5)Ο€

(107+0.5)Ο€

(kFR

)2

kBT

( 1 T1

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 2 / 4

Page 27: Numerical Renormalization Group computation of magnetic relaxation rates

Additional results

Relaxation rate - 𝒒𝑆𝐸𝑇 (𝑇 ) profile

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1

kB T

0

1

2

3

4

5

6

7

101 Ο€

102 Ο€

103 Ο€

104 Ο€

105 Ο€

106 Ο€

107 Ο€

(kFR

)2

kBT

( 1 T1

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 3 / 4

Page 28: Numerical Renormalization Group computation of magnetic relaxation rates

Additional results

Particle-hole symmetric case

Particle-hole symmetric case: 1/𝑇1 as function of 𝑇

π‘˜πΉπ‘… = π‘›πœ‹ and π‘˜πΉπ‘… = (𝑛+ 12 )πœ‹, 𝑛 = 10

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1

kB T

0

1

2

3

4

5

6

7

10-9 10-8 10-71.4

1.6

1.8

2.0

(kFR

)2

kBT

( 1 T1

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 4 / 4

Page 29: Numerical Renormalization Group computation of magnetic relaxation rates

Additional results

Particle-hole symmetric case

Particle-hole symmetric case: 1/𝑇1 as function of 𝑇

π‘˜πΉπ‘… = π‘›πœ‹ and π‘˜πΉπ‘… = (𝑛+ 12 )πœ‹, 𝑛 = 103

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1

kB T

0

1

2

3

4

5

6

7

10-8 10-71.4

1.6

1.8

2.0

(kFR

)2

kBT

( 1 T1

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 4 / 4

Page 30: Numerical Renormalization Group computation of magnetic relaxation rates

Additional results

Particle-hole symmetric case

Particle-hole symmetric case: 1/𝑇1 as function of 𝑇

π‘˜πΉπ‘… = π‘›πœ‹ and π‘˜πΉπ‘… = (𝑛+ 12 )πœ‹, 𝑛 = 105

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1

kB T

0

1

2

3

4

5

6

7

10-7

1.6

1.8

2.0

(kFR

)2

kBT

( 1 T1

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 4 / 4

Page 31: Numerical Renormalization Group computation of magnetic relaxation rates

Additional results

Particle-hole symmetric case

Particle-hole symmetric case: 1/𝑇1 as function of 𝑇

π‘˜πΉπ‘… = π‘›πœ‹ and π‘˜πΉπ‘… = (𝑛+ 12 )πœ‹, 𝑛 = 107

10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1

kB T

0

1

2

3

4

5

6

7

10-91

2

3

4

(kFR

)2

kBT

( 1 T1

)

Zawadzki, K. de; Oliveira, L.N.; Pinto, J.W.M. NRG computation of nuclear magnetic relaxation rates 4 / 4